Introduction ============ This directory contains Device Tree overlays. Device Tree makes it possible to support many hardware configurations with a single kernel and without the need to explicitly load or blacklist kernel modules. Note that this isn't a "pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices are still configured by the board support code, but the intention is to eventually reach that goal. On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By default, the Raspberry Pi kernel boots with device tree enabled. You can completely disable DT usage (for now) by adding: device_tree= to your config.txt, which should cause your Pi to revert to the old way of doing things after a reboot. In /boot you will find a .dtb for each base platform. This describes the hardware that is part of the Raspberry Pi board. The loader (start.elf and its siblings) selects the .dtb file appropriate for the platform by name, and reads it into memory. At this point, all of the optional interfaces (i2c, i2s, spi) are disabled, but they can be enabled using Device Tree parameters: dtparam=i2c=on,i2s=on,spi=on However, this shouldn't be necessary in many use cases because loading an overlay that requires one of those interfaces will cause it to be enabled automatically, and it is advisable to only enable interfaces if they are needed. Configuring additional, optional hardware is done using Device Tree overlays (see below). GPIO numbering uses the hardware pin numbering scheme (aka BCM scheme) and not the physical pin numbers. raspi-config ============ The Advanced Options section of the raspi-config utility can enable and disable Device Tree use, as well as toggling the I2C and SPI interfaces. Note that it is possible to both enable an interface and blacklist the driver, if for some reason you should want to defer the loading. Modules ======= As well as describing the hardware, Device Tree also gives enough information to allow suitable driver modules to be located and loaded, with the corollary that unneeded modules are not loaded. As a result it should be possible to remove lines from /etc/modules, and /etc/modprobe.d/raspi-blacklist.conf can have its contents deleted (or commented out). Using Overlays ============== Overlays are loaded using the "dtoverlay" config.txt setting. As an example, consider I2C Real Time Clock drivers. In the pre-DT world these would be loaded by writing a magic string comprising a device identifier and an I2C address to a special file in /sys/class/i2c-adapter, having first loaded the driver for the I2C interface and the RTC device - something like this: modprobe i2c-bcm2835 modprobe rtc-ds1307 echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device With DT enabled, this becomes a line in config.txt: dtoverlay=i2c-rtc,ds1307 This causes the file /boot/overlays/i2c-rtc.dtbo to be loaded and a "node" describing the DS1307 I2C device to be added to the Device Tree for the Pi. By default it usees address 0x68, but this can be modified with an additional DT parameter: dtoverlay=i2c-rtc,ds1307,addr=0x68 Parameters usually have default values, although certain parameters are mandatory. See the list of overlays below for a description of the parameters and their defaults. The Overlay and Parameter Reference =================================== N.B. When editing this file, please preserve the indentation levels to make it simple to parse programmatically. NO HARD TABS. Name: Info: Configures the base Raspberry Pi hardware Load: Params: audio Set to "on" to enable the onboard ALSA audio interface (default "off") axiperf Set to "on" to enable the AXI bus performance monitors. See /sys/kernel/debug/raspberrypi_axi_monitor for the results. eee Enable Energy Efficient Ethernet support for compatible devices (default "on"). See also "tx_lpi_timer". Pi3B+ only. eth_downshift_after Set the number of auto-negotiation failures after which the 1000Mbps modes are disabled. Legal values are 2, 3, 4, 5 and 0, where 0 means never downshift (default 2). Pi3B+ only. eth_led0 Set mode of LED0 - amber on Pi3B+ (default "1"), green on Pi4 (default "0"). The legal values are: Pi3B+ 0=link/activity 1=link1000/activity 2=link100/activity 3=link10/activity 4=link100/1000/activity 5=link10/1000/activity 6=link10/100/activity 14=off 15=on Pi4 0=Speed/Activity 1=Speed 2=Flash activity 3=FDX 4=Off 5=On 6=Alt 7=Speed/Flash 8=Link 9=Activity eth_led1 Set mode of LED1 - green on Pi3B (default "6"), amber on Pi4 (default "8"). See eth_led0 for legal values. eth_max_speed Set the maximum speed a link is allowed to negotiate. Legal values are 10, 100 and 1000 (default 1000). Pi3B+ only. i2c_arm Set to "on" to enable the ARM's i2c interface (default "off") i2c_vc Set to "on" to enable the i2c interface usually reserved for the VideoCore processor (default "off") i2c An alias for i2c_arm i2c_arm_baudrate Set the baudrate of the ARM's i2c interface (default "100000") i2c_vc_baudrate Set the baudrate of the VideoCore i2c interface (default "100000") i2c_baudrate An alias for i2c_arm_baudrate i2s Set to "on" to enable the i2s interface (default "off") spi Set to "on" to enable the spi interfaces (default "off") random Set to "on" to enable the hardware random number generator (default "on") sd_overclock Clock (in MHz) to use when the MMC framework requests 50MHz sd_poll_once Looks for a card once after booting. Useful for network booting scenarios to avoid the overhead of continuous polling. N.B. Using this option restricts the system to using a single card per boot (or none at all). (default off) sd_force_pio Disable DMA support for SD driver (default off) sd_pio_limit Number of blocks above which to use DMA for SD card (default 1) sd_debug Enable debug output from SD driver (default off) sdio_overclock Clock (in MHz) to use when the MMC framework requests 50MHz for the SDIO/WiFi interface. tx_lpi_timer Set the delay in microseconds between going idle and entering the low power state (default 600). Requires EEE to be enabled - see "eee". uart0 Set to "off" to disable uart0 (default "on") uart1 Set to "on" or "off" to enable or disable uart1 (default varies) watchdog Set to "on" to enable the hardware watchdog (default "off") act_led_trigger Choose which activity the LED tracks. Use "heartbeat" for a nice load indicator. (default "mmc") act_led_activelow Set to "on" to invert the sense of the LED (default "off") N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led overlay. act_led_gpio Set which GPIO to use for the activity LED (in case you want to connect it to an external device) (default "16" on a non-Plus board, "47" on a Plus or Pi 2) N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led overlay. pwr_led_trigger pwr_led_activelow pwr_led_gpio As for act_led_*, but using the PWR LED. Not available on Model A/B boards. N.B. It is recommended to only enable those interfaces that are needed. Leaving all interfaces enabled can lead to unwanted behaviour (i2c_vc interfering with Pi Camera, I2S and SPI hogging GPIO pins, etc.) Note also that i2c, i2c_arm and i2c_vc are aliases for the physical interfaces i2c0 and i2c1. Use of the numeric variants is still possible but deprecated because the ARM/VC assignments differ between board revisions. The same board-specific mapping applies to i2c_baudrate, and the other i2c baudrate parameters. Name: act-led Info: Pi 3B, 3B+, 3A+ and 4B use a GPIO expander to drive the LEDs which can only be accessed from the VPU. There is a special driver for this with a separate DT node, which has the unfortunate consequence of breaking the act_led_gpio and act_led_activelow dtparams. This overlay changes the GPIO controller back to the standard one and restores the dtparams. Load: dtoverlay=act-led,= Params: activelow Set to "on" to invert the sense of the LED (default "off") gpio Set which GPIO to use for the activity LED (in case you want to connect it to an external device) REQUIRED Name: adau1977-adc Info: Overlay for activation of ADAU1977 ADC codec over I2C for control and I2S for data. Load: dtoverlay=adau1977-adc Params: Name: adau7002-simple Info: Overlay for the activation of ADAU7002 stereo PDM to I2S converter. Load: dtoverlay=adau7002-simple,= Params: card-name Override the default, "adau7002", card name. Name: ads1015 Info: Overlay for activation of Texas Instruments ADS1015 ADC over I2C Load: dtoverlay=ads1015,= Params: addr I2C bus address of device. Set based on how the addr pin is wired. (default=0x48 assumes addr is pulled to GND) cha_enable Enable virtual channel a. (default=true) cha_cfg Set the configuration for virtual channel a. (default=4 configures this channel for the voltage at A0 with respect to GND) cha_datarate Set the datarate (samples/sec) for this channel. (default=4 sets 1600 sps) cha_gain Set the gain of the Programmable Gain Amplifier for this channel. (default=2 sets the full scale of the channel to 2.048 Volts) Channel (ch) parameters can be set for each enabled channel. A maximum of 4 channels can be enabled (letters a thru d). For more information refer to the device datasheet at: http://www.ti.com/lit/ds/symlink/ads1015.pdf Name: ads1115 Info: Texas Instruments ADS1115 ADC Load: dtoverlay=ads1115,[=] Params: addr I2C bus address of device. Set based on how the addr pin is wired. (default=0x48 assumes addr is pulled to GND) cha_enable Enable virtual channel a. cha_cfg Set the configuration for virtual channel a. (default=4 configures this channel for the voltage at A0 with respect to GND) cha_datarate Set the datarate (samples/sec) for this channel. (default=7 sets 860 sps) cha_gain Set the gain of the Programmable Gain Amplifier for this channel. (Default 1 sets the full scale of the channel to 4.096 Volts) Channel parameters can be set for each enabled channel. A maximum of 4 channels can be enabled (letters a thru d). For more information refer to the device datasheet at: http://www.ti.com/lit/ds/symlink/ads1115.pdf Name: ads7846 Info: ADS7846 Touch controller Load: dtoverlay=ads7846,= Params: cs SPI bus Chip Select (default 1) speed SPI bus speed (default 2MHz, max 3.25MHz) penirq GPIO used for PENIRQ. REQUIRED penirq_pull Set GPIO pull (default 0=none, 2=pullup) swapxy Swap x and y axis xmin Minimum value on the X axis (default 0) ymin Minimum value on the Y axis (default 0) xmax Maximum value on the X axis (default 4095) ymax Maximum value on the Y axis (default 4095) pmin Minimum reported pressure value (default 0) pmax Maximum reported pressure value (default 65535) xohms Touchpanel sensitivity (X-plate resistance) (default 400) penirq is required and usually xohms (60-100) has to be set as well. Apart from that, pmax (255) and swapxy are also common. The rest of the calibration can be done with xinput-calibrator. See: github.com/notro/fbtft/wiki/FBTFT-on-Raspian Device Tree binding document: www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt Name: adv7282m Info: Analog Devices ADV7282M analogue video to CSI2 bridge. Uses Unicam1, which is the standard camera connector on most Pi variants. Load: dtoverlay=adv7282m,= Params: i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. addr Overrides the I2C address (default 0x21) Name: adv728x-m Info: Analog Devices ADV728[0|1|2]-M analogue video to CSI2 bridges. This is a wrapper for adv7282m, and defaults to ADV7282M. Load: dtoverlay=adv728x-m,= Params: i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. addr Overrides the I2C address (default 0x21) adv7280m Select ADV7280-M. adv7281m Select ADV7281-M. adv7281ma Select ADV7281-MA. Name: akkordion-iqdacplus Info: Configures the Digital Dreamtime Akkordion Music Player (based on the OEM IQAudIO DAC+ or DAC Zero module). Load: dtoverlay=akkordion-iqdacplus,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with dtoverlay=akkordion-iqdacplus,24db_digital_gain (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: allo-boss-dac-pcm512x-audio Info: Configures the Allo Boss DAC audio cards. Load: dtoverlay=allo-boss-dac-pcm512x-audio, Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=allo-boss-dac-pcm512x-audio, 24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) slave Force Boss DAC into slave mode, using Pi a master for bit clock and frame clock. Enable with "dtoverlay=allo-boss-dac-pcm512x-audio, slave" Name: allo-digione Info: Configures the Allo Digione audio card Load: dtoverlay=allo-digione Params: Name: allo-katana-dac-audio Info: Configures the Allo Katana DAC audio card Load: dtoverlay=allo-katana-dac-audio Params: Name: allo-piano-dac-pcm512x-audio Info: Configures the Allo Piano DAC (2.0/2.1) audio cards. (NB. This initial support is for 2.0 channel audio ONLY! ie. stereo. The subwoofer outputs on the Piano 2.1 are not currently supported!) Load: dtoverlay=allo-piano-dac-pcm512x-audio, Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: allo-piano-dac-plus-pcm512x-audio Info: Configures the Allo Piano DAC (2.1) audio cards. Load: dtoverlay=allo-piano-dac-plus-pcm512x-audio, Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) glb_mclk This option is only with Kali board. If enabled, MCLK for Kali is used and PLL is disabled for better voice quality. (default Off) Name: anyspi Info: Universal device tree overlay for SPI devices Just specify the SPI address and device name ("compatible" property). This overlay lacks any device-specific parameter support! For devices on spi1 or spi2, the interfaces should be enabled with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays. Examples: 1. SPI NOR flash on spi0.1, maximum SPI clock frequency 45MHz: dtoverlay=anyspi:spi0-1,dev="jedec,spi-nor",speed=45000000 2. MCP3204 ADC on spi1.2, maximum SPI clock frequency 500kHz: dtoverlay=anyspi:spi1-2,dev="microchip,mcp3204" Load: dtoverlay=anyspi,= Params: spi- Configure device at spi, cs (boolean, required) dev Set device name to search compatible module (string, required) speed Set SPI clock frequency in Hz (integer, optional, default 500000) Name: apds9960 Info: Configures the AVAGO APDS9960 digital proximity, ambient light, RGB and gesture sensor Load: dtoverlay=apds9960,= Params: gpiopin GPIO used for INT (default 4) noints Disable the interrupt GPIO line. Name: applepi-dac Info: Configures the Orchard Audio ApplePi-DAC audio card Load: dtoverlay=applepi-dac Params: Name: at86rf233 Info: Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver, connected to spi0.0 Load: dtoverlay=at86rf233,= Params: interrupt GPIO used for INT (default 23) reset GPIO used for Reset (default 24) sleep GPIO used for Sleep (default 25) speed SPI bus speed in Hz (default 3000000) trim Fine tuning of the internal capacitance arrays (0=+0pF, 15=+4.5pF, default 15) Name: audioinjector-addons Info: Configures the audioinjector.net audio add on soundcards Load: dtoverlay=audioinjector-addons,= Params: non-stop-clocks Keeps the clocks running even when the stream is paused or stopped (default off) Name: audioinjector-ultra Info: Configures the audioinjector.net ultra soundcard Load: dtoverlay=audioinjector-ultra Params: Name: audioinjector-wm8731-audio Info: Configures the audioinjector.net audio add on soundcard Load: dtoverlay=audioinjector-wm8731-audio Params: Name: audiosense-pi Info: Configures the audiosense-pi add on soundcard For more information refer to https://gitlab.com/kakar0t/audiosense-pi Load: dtoverlay=audiosense-pi Params: Name: audremap Info: Switches PWM sound output to GPIOs on the 40-pin header Load: dtoverlay=audremap,= Params: swap_lr Reverse the channel allocation, which will also swap the audio jack outputs (default off) enable_jack Don't switch off the audio jack output (default off) pins_12_13 Select GPIOs 12 & 13 (default) pins_18_19 Select GPIOs 18 & 19 Name: balena-fin Info: Overlay that enables WiFi, Bluetooth and the GPIO expander on the balenaFin carrier board for the Raspberry Pi Compute Module 3/3+ Lite. Load: dtoverlay=balena-fin Params: Name: bmp085_i2c-sensor Info: This overlay is now deprecated - see i2c-sensor Load: Name: dht11 Info: Overlay for the DHT11/DHT21/DHT22 humidity/temperature sensors Also sometimes found with the part number(s) AM230x. Load: dtoverlay=dht11,= Params: gpiopin GPIO connected to the sensor's DATA output. (default 4) Name: dionaudio-loco Info: Configures the Dion Audio LOCO DAC-AMP Load: dtoverlay=dionaudio-loco Params: Name: dionaudio-loco-v2 Info: Configures the Dion Audio LOCO-V2 DAC-AMP Load: dtoverlay=dionaudio-loco-v2,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=hifiberry-dacplus,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: disable-bt Info: Disable onboard Bluetooth on Pi 3B, 3B+, 3A+, 4B and Zero W, restoring UART0/ttyAMA0 over GPIOs 14 & 15. N.B. To disable the systemd service that initialises the modem so it doesn't use the UART, use 'sudo systemctl disable hciuart'. Load: dtoverlay=disable-bt Params: Name: disable-wifi Info: Disable onboard WiFi on Pi 3B, 3B+, 3A+, 4B and Zero W. Load: dtoverlay=disable-wifi Params: Name: dpi18 Info: Overlay for a generic 18-bit DPI display This uses GPIOs 0-21 (so no I2C, uart etc.), and activates the output 2-3 seconds after the kernel has started. Load: dtoverlay=dpi18 Params: Name: dpi24 Info: Overlay for a generic 24-bit DPI display This uses GPIOs 0-27 (so no I2C, uart etc.), and activates the output 2-3 seconds after the kernel has started. Load: dtoverlay=dpi24 Params: Name: draws Info: Configures the NW Digital Radio DRAWS Hat The board includes an ADC to measure various board values and also provides two analog user inputs on the expansion header. The ADC can be configured for various sample rates and gain values to adjust the input range. Tables describing the two parameters follow. ADC Gain Values: 0 = +/- 6.144V 1 = +/- 4.096V 2 = +/- 2.048V 3 = +/- 1.024V 4 = +/- 0.512V 5 = +/- 0.256V 6 = +/- 0.256V 7 = +/- 0.256V ADC Datarate Values: 0 = 128sps 1 = 250sps 2 = 490sps 3 = 920sps 4 = 1600sps (default) 5 = 2400sps 6 = 3300sps 7 = 3300sps Load: dtoverlay=draws,= Params: draws_adc_ch4_gain Sets the full scale resolution of the ADCs input voltage sensor (default 1) draws_adc_ch4_datarate Sets the datarate of the ADCs input voltage sensor draws_adc_ch5_gain Sets the full scale resolution of the ADCs 5V rail voltage sensor (default 1) draws_adc_ch5_datarate Sets the datarate of the ADCs 4V rail voltage sensor draws_adc_ch6_gain Sets the full scale resolution of the ADCs AIN2 input (default 2) draws_adc_ch6_datarate Sets the datarate of the ADCs AIN2 input draws_adc_ch7_gain Sets the full scale resolution of the ADCs AIN3 input (default 2) draws_adc_ch7_datarate Sets the datarate of the ADCs AIN3 input alsaname Name of the ALSA audio device (default "draws") Name: dwc-otg Info: Selects the dwc_otg USB controller driver which has fiq support. This is the default on all except the Pi Zero which defaults to dwc2. Load: dtoverlay=dwc-otg Params: Name: dwc2 Info: Selects the dwc2 USB controller driver Load: dtoverlay=dwc2,= Params: dr_mode Dual role mode: "host", "peripheral" or "otg" g-rx-fifo-size Size of rx fifo size in gadget mode g-np-tx-fifo-size Size of non-periodic tx fifo size in gadget mode [ The ds1307-rtc overlay has been deleted. See i2c-rtc. ] Name: enc28j60 Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI0 Load: dtoverlay=enc28j60,= Params: int_pin GPIO used for INT (default 25) speed SPI bus speed (default 12000000) Name: enc28j60-spi2 Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI2 Load: dtoverlay=enc28j60-spi2,= Params: int_pin GPIO used for INT (default 39) speed SPI bus speed (default 12000000) Name: exc3000 Info: Enables I2C connected EETI EXC3000 multiple touch controller using GPIO 4 (pin 7 on GPIO header) for interrupt. Load: dtoverlay=exc3000,= Params: interrupt GPIO used for interrupt (default 4) sizex Touchscreen size x (default 4096) sizey Touchscreen size y (default 4096) invx Touchscreen inverted x axis invy Touchscreen inverted y axis swapxy Touchscreen swapped x y axis Name: fe-pi-audio Info: Configures the Fe-Pi Audio Sound Card Load: dtoverlay=fe-pi-audio Params: Name: goodix Info: Enables I2C connected Goodix gt9271 multiple touch controller using GPIOs 4 and 17 (pins 7 and 11 on GPIO header) for interrupt and reset. Load: dtoverlay=goodix,= Params: interrupt GPIO used for interrupt (default 4) reset GPIO used for reset (default 17) Name: googlevoicehat-soundcard Info: Configures the Google voiceHAT soundcard Load: dtoverlay=googlevoicehat-soundcard Params: Name: gpio-fan Info: Configure a GPIO pin to control a cooling fan. Load: dtoverlay=gpio-fan,= Params: gpiopin GPIO used to control the fan (default 12) temp Temperature at which the fan switches on, in millicelcius (default 55000) Name: gpio-ir Info: Use GPIO pin as rc-core style infrared receiver input. The rc-core- based gpio_ir_recv driver maps received keys directly to a /dev/input/event* device, all decoding is done by the kernel - LIRC is not required! The key mapping and other decoding parameters can be configured by "ir-keytable" tool. Load: dtoverlay=gpio-ir,= Params: gpio_pin Input pin number. Default is 18. gpio_pull Desired pull-up/down state (off, down, up) Default is "up". invert "1" = invert the input (active-low signalling). "0" = non-inverted input (active-high signalling). Default is "1". rc-map-name Default rc keymap (can also be changed by ir-keytable), defaults to "rc-rc6-mce" Name: gpio-ir-tx Info: Use GPIO pin as bit-banged infrared transmitter output. This is an alternative to "pwm-ir-tx". gpio-ir-tx doesn't require a PWM so it can be used together with onboard analog audio. Load: dtoverlay=gpio-ir-tx,= Params: gpio_pin Output GPIO (default 18) invert "1" = invert the output (make it active-low). Default is "0" (active-high). Name: gpio-key Info: This is a generic overlay for activating GPIO keypresses using the gpio-keys library and this dtoverlay. Multiple keys can be set up using multiple calls to the overlay for configuring additional buttons or joysticks. You can see available keycodes at https://github.com/torvalds/linux/blob/v4.12/include/uapi/ linux/input-event-codes.h#L64 Load: dtoverlay=gpio-key,= Params: gpio GPIO pin to trigger on (default 3) active_low When this is 1 (active low), a falling edge generates a key down event and a rising edge generates a key up event. When this is 0 (active high), this is reversed. The default is 1 (active low) gpio_pull Desired pull-up/down state (off, down, up) Default is "up". Note that the default pin (GPIO3) has an external pullup label Set a label for the key keycode Set the key code for the button Name: gpio-no-bank0-irq Info: Use this overlay to disable GPIO interrupts for GPIOs in bank 0 (0-27), which can be useful for UIO drivers. N.B. Using this overlay will trigger a kernel WARN during booting, but this can safely be ignored - the system should work as expected. Load: dtoverlay=gpio-no-bank0-irq Params: Name: gpio-no-irq Info: Use this overlay to disable all GPIO interrupts, which can be useful for user-space GPIO edge detection systems. Load: dtoverlay=gpio-no-irq Params: Name: gpio-poweroff Info: Drives a GPIO high or low on poweroff (including halt). Enabling this overlay will prevent the ability to boot by driving GPIO3 low. Load: dtoverlay=gpio-poweroff,= Params: gpiopin GPIO for signalling (default 26) active_low Set if the power control device requires a high->low transition to trigger a power-down. Note that this will require the support of a custom dt-blob.bin to prevent a power-down during the boot process, and that a reboot will also cause the pin to go low. input Set if the gpio pin should be configured as an input. export Set to export the configured pin to sysfs timeout_ms Specify (in ms) how long the kernel waits for power-down before issuing a WARN (default 3000). Name: gpio-shutdown Info: Initiates a shutdown when GPIO pin changes. The given GPIO pin is configured as an input key that generates KEY_POWER events. This event is handled by systemd-logind by initiating a shutdown. Systemd versions older than 225 need an udev rule enable listening to the input device: ACTION!="REMOVE", SUBSYSTEM=="input", KERNEL=="event*", \ SUBSYSTEMS=="platform", DRIVERS=="gpio-keys", \ ATTRS{keys}=="116", TAG+="power-switch" This overlay only handles shutdown. After shutdown, the system can be powered up again by driving GPIO3 low. The default configuration uses GPIO3 with a pullup, so if you connect a button between GPIO3 and GND (pin 5 and 6 on the 40-pin header), you get a shutdown and power-up button. Load: dtoverlay=gpio-shutdown,= Params: gpio_pin GPIO pin to trigger on (default 3) active_low When this is 1 (active low), a falling edge generates a key down event and a rising edge generates a key up event. When this is 0 (active high), this is reversed. The default is 1 (active low). gpio_pull Desired pull-up/down state (off, down, up) Default is "up". Note that the default pin (GPIO3) has an external pullup. debounce Specify the debounce interval in milliseconds (default 100) Name: hd44780-lcd Info: Configures an HD44780 compatible LCD display. Uses 4 gpio pins for data, 2 gpio pins for enable and register select and 1 optional pin for enabling/disabling the backlight display. Load: dtoverlay=hd44780-lcd,= Params: pin_d4 GPIO pin for data pin D4 (default 6) pin_d5 GPIO pin for data pin D5 (default 13) pin_d6 GPIO pin for data pin D6 (default 19) pin_d7 GPIO pin for data pin D7 (default 26) pin_en GPIO pin for "Enable" (default 21) pin_rs GPIO pin for "Register Select" (default 20) pin_bl Optional pin for enabling/disabling the display backlight. (default disabled) display_height Height of the display in characters display_width Width of the display in characters Name: hdmi-backlight-hwhack-gpio Info: Devicetree overlay for GPIO based backlight on/off capability. Use this if you have one of those HDMI displays whose backlight cannot be controlled via DPMS over HDMI and plan to do a little soldering to use an RPi gpio pin for on/off switching. See: https://www.waveshare.com/wiki/7inch_HDMI_LCD_(C)#Backlight_Control Load: dtoverlay=hdmi-backlight-hwhack-gpio,= Params: gpio_pin GPIO pin used (default 17) active_low Set this to 1 if the display backlight is switched on when the wire goes low. Leave the default (value 0) if the backlight expects a high to switch it on. Name: hifiberry-amp Info: Configures the HifiBerry Amp and Amp+ audio cards Load: dtoverlay=hifiberry-amp Params: Name: hifiberry-dac Info: Configures the HifiBerry DAC audio card Load: dtoverlay=hifiberry-dac Params: Name: hifiberry-dacplus Info: Configures the HifiBerry DAC+ audio card Load: dtoverlay=hifiberry-dacplus,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=hifiberry-dacplus,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) slave Force DAC+ Pro into slave mode, using Pi as master for bit clock and frame clock. leds_off If set to 'true' the onboard indicator LEDs are switched off at all times. Name: hifiberry-dacplusadc Info: Configures the HifiBerry DAC+ADC audio card Load: dtoverlay=hifiberry-dacplusadc,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=hifiberry-dacplus,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) slave Force DAC+ Pro into slave mode, using Pi as master for bit clock and frame clock. leds_off If set to 'true' the onboard indicator LEDs are switched off at all times. Name: hifiberry-dacplusadcpro Info: Configures the HifiBerry DAC+ADC PRO audio card Load: dtoverlay=hifiberry-dacplusadcpro,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=hifiberry-dacplusadcpro,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) slave Force DAC+ADC Pro into slave mode, using Pi as master for bit clock and frame clock. leds_off If set to 'true' the onboard indicator LEDs are switched off at all times. Name: hifiberry-dacplusdsp Info: Configures the HifiBerry DAC+DSP audio card Load: dtoverlay=hifiberry-dacplusdsp Params: Name: hifiberry-dacplushd Info: Configures the HifiBerry DAC+ HD audio card Load: dtoverlay=hifiberry-dacplushd Params: Name: hifiberry-digi Info: Configures the HifiBerry Digi and Digi+ audio card Load: dtoverlay=hifiberry-digi Params: Name: hifiberry-digi-pro Info: Configures the HifiBerry Digi+ Pro audio card Load: dtoverlay=hifiberry-digi-pro Params: Name: hy28a Info: HY28A - 2.8" TFT LCD Display Module by HAOYU Electronics Default values match Texy's display shield Load: dtoverlay=hy28a,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) resetgpio GPIO used to reset controller ledgpio GPIO used to control backlight Name: hy28b Info: HY28B - 2.8" TFT LCD Display Module by HAOYU Electronics Default values match Texy's display shield Load: dtoverlay=hy28b,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) resetgpio GPIO used to reset controller ledgpio GPIO used to control backlight Name: hy28b-2017 Info: HY28B 2017 version - 2.8" TFT LCD Display Module by HAOYU Electronics Default values match Texy's display shield Load: dtoverlay=hy28b-2017,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) resetgpio GPIO used to reset controller ledgpio GPIO used to control backlight Name: i-sabre-q2m Info: Configures the Audiophonics I-SABRE Q2M DAC Load: dtoverlay=i-sabre-q2m Params: Name: i2c-bcm2708 Info: Fall back to the i2c_bcm2708 driver for the i2c_arm bus. Load: dtoverlay=i2c-bcm2708 Params: Name: i2c-gpio Info: Adds support for software i2c controller on gpio pins Load: dtoverlay=i2c-gpio,= Params: i2c_gpio_sda GPIO used for I2C data (default "23") i2c_gpio_scl GPIO used for I2C clock (default "24") i2c_gpio_delay_us Clock delay in microseconds (default "2" = ~100kHz) bus Set to a unique, non-zero value if wanting multiple i2c-gpio busses. If set, will be used as the preferred bus number (/dev/i2c-). If not set, the default value is 0, but the bus number will be dynamically assigned - probably 3. Name: i2c-mux Info: Adds support for a number of I2C bus multiplexers on i2c_arm Load: dtoverlay=i2c-mux,= Params: pca9542 Select the NXP PCA9542 device pca9545 Select the NXP PCA9545 device pca9548 Select the NXP PCA9548 device addr Change I2C address of the device (default 0x70) [ The i2c-mux-pca9548a overlay has been deleted. See i2c-mux. ] Name: i2c-pwm-pca9685a Info: Adds support for an NXP PCA9685A I2C PWM controller on i2c_arm Load: dtoverlay=i2c-pwm-pca9685a,= Params: addr I2C address of PCA9685A (default 0x40) Name: i2c-rtc Info: Adds support for a number of I2C Real Time Clock devices Load: dtoverlay=i2c-rtc,= Params: abx80x Select one of the ABx80x family: AB0801, AB0803, AB0804, AB0805, AB1801, AB1803, AB1804, AB1805 ds1307 Select the DS1307 device ds1339 Select the DS1339 device ds3231 Select the DS3231 device m41t62 Select the M41T62 device mcp7940x Select the MCP7940x device mcp7941x Select the MCP7941x device pcf2127 Select the PCF2127 device pcf2129 Select the PCF2129 device pcf8523 Select the PCF8523 device pcf85363 Select the PCF85363 device pcf8563 Select the PCF8563 device rv3028 Select the Micro Crystal RV3028 device addr Sets the address for the RTC. Note that the device must be configured to use the specified address. trickle-diode-type Diode type for trickle charge - "standard" or "schottky" (ABx80x only) trickle-resistor-ohms Resistor value for trickle charge (DS1339, ABx80x, RV3028) wakeup-source Specify that the RTC can be used as a wakeup source backup-switchover-mode Backup power supply switch mode. Must be 0 for off or 1 for Vdd < VBackup (RV3028 only) Name: i2c-rtc-gpio Info: Adds support for a number of I2C Real Time Clock devices using the software i2c controller Load: dtoverlay=i2c-rtc-gpio,= Params: abx80x Select one of the ABx80x family: AB0801, AB0803, AB0804, AB0805, AB1801, AB1803, AB1804, AB1805 ds1307 Select the DS1307 device ds1339 Select the DS1339 device ds3231 Select the DS3231 device m41t62 Select the M41T62 device mcp7940x Select the MCP7940x device mcp7941x Select the MCP7941x device pcf2127 Select the PCF2127 device pcf2129 Select the PCF2129 device pcf8523 Select the PCF8523 device pcf8563 Select the PCF8563 device rv3028 Select the Micro Crystal RV3028 device addr Sets the address for the RTC. Note that the device must be configured to use the specified address. trickle-diode-type Diode type for trickle charge - "standard" or "schottky" (ABx80x only) trickle-resistor-ohms Resistor value for trickle charge (DS1339, ABx80x, RV3028) wakeup-source Specify that the RTC can be used as a wakeup source backup-switchover-mode Backup power supply switch mode. Must be 0 for off or 1 for Vdd < VBackup (RV3028 only) i2c_gpio_sda GPIO used for I2C data (default "23") i2c_gpio_scl GPIO used for I2C clock (default "24") i2c_gpio_delay_us Clock delay in microseconds (default "2" = ~100kHz) Name: i2c-sensor Info: Adds support for a number of I2C barometric pressure and temperature sensors on i2c_arm Load: dtoverlay=i2c-sensor,= Params: addr Set the address for the BME280, BME680, BMP280, DS1621, HDC100X, LM75, SHT3x or TMP102 bme280 Select the Bosch Sensortronic BME280 Valid addresses 0x76-0x77, default 0x76 bme680 Select the Bosch Sensortronic BME680 Valid addresses 0x76-0x77, default 0x76 bmp085 Select the Bosch Sensortronic BMP085 bmp180 Select the Bosch Sensortronic BMP180 bmp280 Select the Bosch Sensortronic BMP280 Valid addresses 0x76-0x77, default 0x76 ds1621 Select the Dallas Semiconductors DS1621 temp sensor. Valid addresses 0x48-0x4f, default 0x48 hdc100x Select the Texas Instruments HDC100x temp sensor Valid addresses 0x40-0x43, default 0x40 htu21 Select the HTU21 temperature and humidity sensor lm75 Select the Maxim LM75 temperature sensor Valid addresses 0x48-0x4f, default 0x4f lm75addr Deprecated - use addr parameter instead max17040 Select the Maxim Integrated MAX17040 battery monitor sht3x Select the Sensiron SHT3x temperature and humidity sensor. Valid addresses 0x44-0x45, default 0x44 si7020 Select the Silicon Labs Si7013/20/21 humidity/ temperature sensor tmp102 Select the Texas Instruments TMP102 temp sensor Valid addresses 0x48-0x4b, default 0x48 tsl4531 Select the AMS TSL4531 digital ambient light sensor veml6070 Select the Vishay VEML6070 ultraviolet light sensor Name: i2c0 Info: Change i2c0 pin usage. Not all pin combinations are usable on all platforms - platforms other then Compute Modules can only use this to disable transaction combining. Load: dtoverlay=i2c0,= Params: pins_0_1 Use pins 0 and 1 (default) pins_28_29 Use pins 28 and 29 pins_44_45 Use pins 44 and 45 pins_46_47 Use pins 46 and 47 combine Allow transactions to be combined (default "yes") Name: i2c0-bcm2708 Info: Deprecated, legacy version of i2c0, from which it inherits its parameters, just adding the explicit individual pin specifiers. Load: Params: sda0_pin GPIO pin for SDA0 (deprecated - use pins_*) scl0_pin GPIO pin for SCL0 (deprecated - use pins_*) Name: i2c1 Info: Change i2c1 pin usage. Not all pin combinations are usable on all platforms - platforms other then Compute Modules can only use this to disable transaction combining. Load: dtoverlay=i2c1,= Params: pins_2_3 Use pins 2 and 3 (default) pins_44_45 Use pins 44 and 45 combine Allow transactions to be combined (default "yes") Name: i2c1-bcm2708 Info: Deprecated, legacy version of i2c1, from which it inherits its parameters, just adding the explicit individual pin specifiers. Load: Params: sda1_pin GPIO pin for SDA1 (2 or 44 - default 2) scl1_pin GPIO pin for SCL1 (3 or 45 - default 3) pin_func Alternative pin function (4 (alt0), 6 (alt2) - default 4) Name: i2c3 Info: Enable the i2c3 bus Load: dtoverlay=i2c3, Params: pins_2_3 Use GPIOs 2 and 3 pins_4_5 Use GPIOs 4 and 5 (default) baudrate Set the baudrate for the interface (default "100000") Name: i2c4 Info: Enable the i2c4 bus Load: dtoverlay=i2c4, Params: pins_6_7 Use GPIOs 6 and 7 pins_8_9 Use GPIOs 8 and 9 (default) baudrate Set the baudrate for the interface (default "100000") Name: i2c5 Info: Enable the i2c5 bus Load: dtoverlay=i2c5, Params: pins_10_11 Use GPIOs 10 and 11 pins_12_13 Use GPIOs 12 and 13 (default) baudrate Set the baudrate for the interface (default "100000") Name: i2c6 Info: Enable the i2c6 bus Load: dtoverlay=i2c6, Params: pins_0_1 Use GPIOs 0 and 1 pins_22_23 Use GPIOs 22 and 23 (default) baudrate Set the baudrate for the interface (default "100000") Name: i2s-gpio28-31 Info: move I2S function block to GPIO 28 to 31 Load: dtoverlay=i2s-gpio28-31 Params: Name: ilitek251x Info: Enables I2C connected Ilitek 251x multiple touch controller using GPIO 4 (pin 7 on GPIO header) for interrupt. Load: dtoverlay=ilitek251x,= Params: interrupt GPIO used for interrupt (default 4) sizex Touchscreen size x, horizontal resolution of touchscreen (in pixels) sizey Touchscreen size y, vertical resolution of touchscreen (in pixels) Name: imx219 Info: Sony IMX219 camera module. Uses Unicam 1, which is the standard camera connector on most Pi variants. Load: dtoverlay=imx219,= Params: i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. Name: iqaudio-codec Info: Configures the IQaudio Codec audio card Load: dtoverlay=iqaudio-codec Params: Name: iqaudio-dac Info: Configures the IQaudio DAC audio card Load: dtoverlay=iqaudio-dac, Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=iqaudio-dac,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: iqaudio-dacplus Info: Configures the IQaudio DAC+ audio card Load: dtoverlay=iqaudio-dacplus,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=iqaudio-dacplus,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24db_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) auto_mute_amp If specified, unmute/mute the IQaudIO amp when starting/stopping audio playback. unmute_amp If specified, unmute the IQaudIO amp once when the DAC driver module loads. Name: iqaudio-digi-wm8804-audio Info: Configures the IQAudIO Digi WM8804 audio card Load: dtoverlay=iqaudio-digi-wm8804-audio,= Params: card_name Override the default, "IQAudIODigi", card name. dai_name Override the default, "IQAudIO Digi", dai name. dai_stream_name Override the default, "IQAudIO Digi HiFi", dai stream name. Name: irs1125 Info: Infineon irs1125 TOF camera module. Uses Unicam 1, which is the standard camera connector on most Pi variants. Load: dtoverlay=irs1125,= Params: i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. Name: jedec-spi-nor Info: Adds support for JEDEC-compliant SPI NOR flash devices. (Note: The "jedec,spi-nor" kernel driver was formerly known as "m25p80".) Load: dtoverlay=jedec-spi-nor,= Params: flash-spi- Enables flash device on SPI, CS#. flash-fastr-spi- Enables flash device with fast read capability on SPI, CS#. Name: justboom-both Info: Simultaneous usage of an justboom-dac and justboom-digi based card Load: dtoverlay=justboom-both,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=justboom-dac,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: justboom-dac Info: Configures the JustBoom DAC HAT, Amp HAT, DAC Zero and Amp Zero audio cards Load: dtoverlay=justboom-dac,= Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec Digital volume control. Enable with "dtoverlay=justboom-dac,24db_digital_gain" (The default behaviour is that the Digital volume control is limited to a maximum of 0dB. ie. it can attenuate but not provide gain. For most users, this will be desired as it will prevent clipping. By appending the 24dB_digital_gain parameter, the Digital volume control will allow up to 24dB of gain. If this parameter is enabled, it is the responsibility of the user to ensure that the Digital volume control is set to a value that does not result in clipping/distortion!) Name: justboom-digi Info: Configures the JustBoom Digi HAT and Digi Zero audio cards Load: dtoverlay=justboom-digi Params: Name: lirc-rpi Info: This overlay has been deprecated and removed - see gpio-ir Load: Name: ltc294x Info: Adds support for the ltc294x family of battery gauges Load: dtoverlay=ltc294x,= Params: ltc2941 Select the ltc2941 device ltc2942 Select the ltc2942 device ltc2943 Select the ltc2943 device ltc2944 Select the ltc2944 device resistor-sense The sense resistor value in milli-ohms. Can be a 32-bit negative value when the battery has been connected to the wrong end of the resistor. prescaler-exponent Range and accuracy of the gauge. The value is programmed into the chip only if it differs from the current setting. For LTC2941 only: - Default value is 128 - the exponent is in the range 0-7 (default 7) See the datasheet for more information. Name: max98357a Info: Configures the Maxim MAX98357A I2S DAC Load: dtoverlay=max98357a,= Params: no-sdmode Driver does not manage the state of the DAC's SD_MODE pin (i.e. chip is always on). sdmode-pin integer, GPIO pin connected to the SD_MODE input of the DAC (default GPIO4 if parameter omitted). Name: mbed-dac Info: Configures the mbed AudioCODEC (TLV320AIC23B) Load: dtoverlay=mbed-dac Params: Name: mcp23017 Info: Configures the MCP23017 I2C GPIO expander Load: dtoverlay=mcp23017,= Params: gpiopin Gpio pin connected to the INTA output of the MCP23017 (default: 4) addr I2C address of the MCP23017 (default: 0x20) mcp23008 Configure an MCP23008 instead. noints Disable the interrupt GPIO line. Name: mcp23s17 Info: Configures the MCP23S08/17 SPI GPIO expanders. If devices are present on SPI1 or SPI2, those interfaces must be enabled with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays. If interrupts are enabled for a device on a given CS# on a SPI bus, that device must be the only one present on that SPI bus/CS#. Load: dtoverlay=mcp23s17,= Params: s08-spi--present 4-bit integer, bitmap indicating MCP23S08 devices present on SPI, CS# s17-spi--present 8-bit integer, bitmap indicating MCP23S17 devices present on SPI, CS# s08-spi--int-gpio integer, enables interrupts on a single MCP23S08 device on SPI, CS#, specifies the GPIO pin to which INT output of MCP23S08 is connected. s17-spi--int-gpio integer, enables mirrored interrupts on a single MCP23S17 device on SPI, CS#, specifies the GPIO pin to which either INTA or INTB output of MCP23S17 is connected. Name: mcp2515-can0 Info: Configures the MCP2515 CAN controller on spi0.0 Load: dtoverlay=mcp2515-can0,= Params: oscillator Clock frequency for the CAN controller (Hz) spimaxfrequency Maximum SPI frequence (Hz) interrupt GPIO for interrupt signal Name: mcp2515-can1 Info: Configures the MCP2515 CAN controller on spi0.1 Load: dtoverlay=mcp2515-can1,= Params: oscillator Clock frequency for the CAN controller (Hz) spimaxfrequency Maximum SPI frequence (Hz) interrupt GPIO for interrupt signal Name: mcp3008 Info: Configures MCP3008 A/D converters For devices on spi1 or spi2, the interfaces should be enabled with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays. Load: dtoverlay=mcp3008,[=] Params: spi--present boolean, configure device at spi, cs spi--speed integer, set the spi bus speed for this device Name: mcp3202 Info: Configures MCP3202 A/D converters For devices on spi1 or spi2, the interfaces should be enabled with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays. Load: dtoverlay=mcp3202,[=] Params: spi--present boolean, configure device at spi, cs spi--speed integer, set the spi bus speed for this device Name: mcp342x Info: Overlay for activation of Microchip MCP3421-3428 ADCs over I2C Load: dtoverlay=mcp342x,= Params: addr I2C bus address of device, for devices with addresses that are configurable, e.g. by hardware links (default=0x68) mcp3421 The device is an MCP3421 mcp3422 The device is an MCP3422 mcp3423 The device is an MCP3423 mcp3424 The device is an MCP3424 mcp3425 The device is an MCP3425 mcp3426 The device is an MCP3426 mcp3427 The device is an MCP3427 mcp3428 The device is an MCP3428 Name: media-center Info: Media Center HAT - 2.83" Touch Display + extras by Pi Supply Load: dtoverlay=media-center,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates xohms Touchpanel sensitivity (X-plate resistance) swapxy Swap x and y axis backlight Change backlight GPIO pin {e.g. 12, 18} gpio_out_pin GPIO for output (default "17") gpio_in_pin GPIO for input (default "18") gpio_in_pull Pull up/down/off on the input pin (default "down") sense Override the IR receive auto-detection logic: "0" = force active-high "1" = force active-low "-1" = use auto-detection (default "-1") softcarrier Turn the software carrier "on" or "off" (default "on") invert "on" = invert the output pin (default "off") debug "on" = enable additional debug messages (default "off") Name: merus-amp Info: Configures the merus-amp audio card Load: dtoverlay=merus-amp Params: Name: midi-uart0 Info: Configures UART0 (ttyAMA0) so that a requested 38.4kbaud actually gets 31.25kbaud, the frequency required for MIDI Load: dtoverlay=midi-uart0 Params: Name: midi-uart1 Info: Configures UART1 (ttyS0) so that a requested 38.4kbaud actually gets 31.25kbaud, the frequency required for MIDI Load: dtoverlay=midi-uart1 Params: Name: miniuart-bt Info: Switch the onboard Bluetooth function on Pi 3B, 3B+, 3A+, 4B and Zero W to use the mini-UART (ttyS0) and restore UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum usable baudrate. N.B. It is also necessary to edit /lib/systemd/system/hciuart.service and replace ttyAMA0 with ttyS0, unless using Raspbian or another distribution with udev rules that create /dev/serial0 and /dev/serial1, in which case use /dev/serial1 instead because it will always be correct. Furthermore, you must also set core_freq and core_freq_min to the same value in config.txt or the miniuart will not work. Load: dtoverlay=miniuart-bt Params: Name: mmc Info: Selects the bcm2835-mmc SD/MMC driver, optionally with overclock Load: dtoverlay=mmc,= Params: overclock_50 Clock (in MHz) to use when the MMC framework requests 50MHz Name: mpu6050 Info: Overlay for i2c connected mpu6050 imu Load: dtoverlay=mpu6050,= Params: interrupt GPIO pin for interrupt (default 4) Name: mz61581 Info: MZ61581 display by Tontec Load: dtoverlay=mz61581,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates txbuflen Transmit buffer length (default 32768) debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) Name: ov5647 Info: Omnivision OV5647 camera module. Uses Unicam 1, which is the standard camera connector on most Pi variants. Load: dtoverlay=ov5647,= Params: i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. Name: papirus Info: PaPiRus ePaper Screen by Pi Supply (both HAT and pHAT) Load: dtoverlay=papirus,= Params: panel Display panel (required): 1.44": e1144cs021 2.0": e2200cs021 2.7": e2271cs021 speed Display SPI bus speed [ The pcf2127-rtc overlay has been deleted. See i2c-rtc. ] [ The pcf8523-rtc overlay has been deleted. See i2c-rtc. ] [ The pcf8563-rtc overlay has been deleted. See i2c-rtc. ] Name: pi3-act-led Info: This overlay has been renamed act-led, keeping pi3-act-led as an alias for backwards compatibility. Load: Name: pi3-disable-bt Info: This overlay has been renamed disable-bt, keeping pi3-disable-bt as an alias for backwards compatibility. Load: Name: pi3-disable-wifi Info: This overlay has been renamed disable-wifi, keeping pi3-disable-wifi as an alias for backwards compatibility. Load: Name: pi3-miniuart-bt Info: This overlay has been renamed miniuart-bt, keeping pi3-miniuart-bt as an alias for backwards compatibility. Load: Name: pibell Info: Configures the pibell audio card. Load: dtoverlay=pibell,= Params: alsaname Set the name as it appears in ALSA (default "PiBell") Name: piglow Info: Configures the PiGlow by pimoroni.com Load: dtoverlay=piglow Params: Name: piscreen Info: PiScreen display by OzzMaker.com Load: dtoverlay=piscreen,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) Name: piscreen2r Info: PiScreen 2 with resistive TP display by OzzMaker.com Load: dtoverlay=piscreen2r,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) Name: pisound Info: Configures the Blokas Labs pisound card Load: dtoverlay=pisound Params: Name: pitft22 Info: Adafruit PiTFT 2.2" screen Load: dtoverlay=pitft22,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} Name: pitft28-capacitive Info: Adafruit PiTFT 2.8" capacitive touch screen Load: dtoverlay=pitft28-capacitive,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} touch-sizex Touchscreen size x (default 240) touch-sizey Touchscreen size y (default 320) touch-invx Touchscreen inverted x axis touch-invy Touchscreen inverted y axis touch-swapxy Touchscreen swapped x y axis Name: pitft28-resistive Info: Adafruit PiTFT 2.8" resistive touch screen Load: dtoverlay=pitft28-resistive,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} Name: pitft35-resistive Info: Adafruit PiTFT 3.5" resistive touch screen Load: dtoverlay=pitft35-resistive,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} Name: pps-gpio Info: Configures the pps-gpio (pulse-per-second time signal via GPIO). Load: dtoverlay=pps-gpio,= Params: gpiopin Input GPIO (default "18") assert_falling_edge When present, assert is indicated by a falling edge, rather than by a rising edge (default off) capture_clear Generate clear events on the trailing edge (default off) Name: pwm Info: Configures a single PWM channel Legal pin,function combinations for each channel: PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1) PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1) N.B.: 1) Pin 18 is the only one available on all platforms, and it is the one used by the I2S audio interface. Pins 12 and 13 might be better choices on an A+, B+ or Pi2. 2) The onboard analogue audio output uses both PWM channels. 3) So be careful mixing audio and PWM. 4) Currently the clock must have been enabled and configured by other means. Load: dtoverlay=pwm,= Params: pin Output pin (default 18) - see table func Pin function (default 2 = Alt5) - see above clock PWM clock frequency (informational) Name: pwm-2chan Info: Configures both PWM channels Legal pin,function combinations for each channel: PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1) PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1) N.B.: 1) Pin 18 is the only one available on all platforms, and it is the one used by the I2S audio interface. Pins 12 and 13 might be better choices on an A+, B+ or Pi2. 2) The onboard analogue audio output uses both PWM channels. 3) So be careful mixing audio and PWM. 4) Currently the clock must have been enabled and configured by other means. Load: dtoverlay=pwm-2chan,= Params: pin Output pin (default 18) - see table pin2 Output pin for other channel (default 19) func Pin function (default 2 = Alt5) - see above func2 Function for pin2 (default 2 = Alt5) clock PWM clock frequency (informational) Name: pwm-ir-tx Info: Use GPIO pin as pwm-assisted infrared transmitter output. This is an alternative to "gpio-ir-tx". pwm-ir-tx makes use of PWM0 to reduce the CPU load during transmission compared to gpio-ir-tx which uses bit-banging. Legal pin,function combinations are: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1) Load: dtoverlay=pwm-ir-tx,= Params: gpio_pin Output GPIO (default 18) func Pin function (default 2 = Alt5) Name: qca7000 Info: I2SE's Evaluation Board for PLC Stamp micro Load: dtoverlay=qca7000,= Params: int_pin GPIO pin for interrupt signal (default 23) speed SPI bus speed (default 12 MHz) Name: rotary-encoder Info: Overlay for GPIO connected rotary encoder. Load: dtoverlay=rotary-encoder,= Params: pin_a GPIO connected to rotary encoder channel A (default 4). pin_b GPIO connected to rotary encoder channel B (default 17). relative_axis register a relative axis rather than an absolute one. Relative axis will only generate +1/-1 events on the input device, hence no steps need to be passed. linux_axis the input subsystem axis to map to this rotary encoder. Defaults to 0 (ABS_X / REL_X) rollover Automatic rollover when the rotary value becomes greater than the specified steps or smaller than 0. For absolute axis only. steps-per-period Number of steps (stable states) per period. The values have the following meaning: 1: Full-period mode (default) 2: Half-period mode 4: Quarter-period mode steps Number of steps in a full turnaround of the encoder. Only relevant for absolute axis. Defaults to 24 which is a typical value for such devices. wakeup Boolean, rotary encoder can wake up the system. encoding String, the method used to encode steps. Supported are "gray" (the default and more common) and "binary". Name: rpi-backlight Info: Raspberry Pi official display backlight driver Load: dtoverlay=rpi-backlight Params: Name: rpi-cirrus-wm5102 Info: Configures the Cirrus Logic Audio Card Load: dtoverlay=rpi-cirrus-wm5102 Params: Name: rpi-dac Info: Configures the RPi DAC audio card Load: dtoverlay=rpi-dac Params: Name: rpi-display Info: RPi-Display - 2.8" Touch Display by Watterott Load: dtoverlay=rpi-display,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} xohms Touchpanel sensitivity (X-plate resistance) swapxy Swap x and y axis backlight Change backlight GPIO pin {e.g. 12, 18} Name: rpi-ft5406 Info: Official Raspberry Pi display touchscreen Load: dtoverlay=rpi-ft5406,= Params: touchscreen-size-x Touchscreen X resolution (default 800) touchscreen-size-y Touchscreen Y resolution (default 600); touchscreen-inverted-x Invert touchscreen X coordinates (default 0); touchscreen-inverted-y Invert touchscreen Y coordinates (default 0); touchscreen-swapped-x-y Swap X and Y cordinates (default 0); Name: rpi-poe Info: Raspberry Pi PoE HAT fan Load: dtoverlay=rpi-poe,[=] Params: poe_fan_temp0 Temperature (in millicelcius) at which the fan turns on (default 50000) poe_fan_temp0_hyst Temperature delta (in millicelcius) at which the fan turns off (default 5000) poe_fan_temp1 Temperature (in millicelcius) at which the fan speeds up (default 55000) poe_fan_temp1_hyst Temperature delta (in millicelcius) at which the fan slows down (default 5000) Name: rpi-proto Info: Configures the RPi Proto audio card Load: dtoverlay=rpi-proto Params: Name: rpi-sense Info: Raspberry Pi Sense HAT Load: dtoverlay=rpi-sense Params: Name: rpi-tv Info: Raspberry Pi TV HAT Load: dtoverlay=rpi-tv Params: Name: rra-digidac1-wm8741-audio Info: Configures the Red Rocks Audio DigiDAC1 soundcard Load: dtoverlay=rra-digidac1-wm8741-audio Params: Name: sc16is750-i2c Info: Overlay for the NXP SC16IS750 UART with I2C Interface Enables the chip on I2C1 at 0x48 (or the "addr" parameter value). To select another address, please refer to table 10 in reference manual. Load: dtoverlay=sc16is750-i2c,= Params: int_pin GPIO used for IRQ (default 24) addr Address (default 0x48) xtal On-board crystal frequency (default 14745600) Name: sc16is752-i2c Info: Overlay for the NXP SC16IS752 dual UART with I2C Interface Enables the chip on I2C1 at 0x48 (or the "addr" parameter value). To select another address, please refer to table 10 in reference manual. Load: dtoverlay=sc16is752-i2c,= Params: int_pin GPIO used for IRQ (default 24) addr Address (default 0x48) xtal On-board crystal frequency (default 14745600) Name: sc16is752-spi1 Info: Overlay for the NXP SC16IS752 Dual UART with SPI Interface Enables the chip on SPI1. N.B.: spi1 is only accessible on devices with a 40pin header, eg: A+, B+, Zero and PI2 B; as well as the Compute Module. Load: dtoverlay=sc16is752-spi1,= Params: int_pin GPIO used for IRQ (default 24) Name: sdhost Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock. N.B. This overlay is designed for situations where the mmc driver is the default, so it disables the other (mmc) interface - this will kill WiFi on a Pi3. If this isn't what you want, either use the sdtweak overlay or the new sd_* dtparams of the base DTBs. Load: dtoverlay=sdhost,= Params: overclock_50 Clock (in MHz) to use when the MMC framework requests 50MHz force_pio Disable DMA support (default off) pio_limit Number of blocks above which to use DMA (default 1) debug Enable debug output (default off) Name: sdio Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock, and enables SDIO via GPIOs 22-27. An example of use in 1-bit mode is "dtoverlay=sdio,bus_width=1,gpios_22_25" Load: dtoverlay=sdio,= Params: sdio_overclock SDIO Clock (in MHz) to use when the MMC framework requests 50MHz poll_once Disable SDIO-device polling every second (default on: polling once at boot-time) bus_width Set the SDIO host bus width (default 4 bits) gpios_22_25 Select GPIOs 22-25 for 1-bit mode. Must be used with bus_width=1. This replaces the sdio-1bit overlay, which is now deprecated. gpios_34_37 Select GPIOs 34-37 for 1-bit mode. Must be used with bus_width=1. gpios_34_39 Select GPIOs 34-39 for 4-bit mode. Must be used with bus_width=4 (the default). Name: sdio-1bit Info: This overlay is now deprecated. Use "dtoverlay=sdio,bus_width=1,gpios_22_25" instead. Load: Name: sdtweak Info: Tunes the bcm2835-sdhost SD/MMC driver N.B. This functionality is now available via the sd_* dtparams in the base DTB. Load: dtoverlay=sdtweak,= Params: overclock_50 Clock (in MHz) to use when the MMC framework requests 50MHz force_pio Disable DMA support (default off) pio_limit Number of blocks above which to use DMA (default 1) debug Enable debug output (default off) poll_once Looks for a card once after booting. Useful for network booting scenarios to avoid the overhead of continuous polling. N.B. Using this option restricts the system to using a single card per boot (or none at all). (default off) enable Set to off to completely disable the interface (default on) Name: sh1106-spi Info: Overlay for SH1106 OLED via SPI using fbtft staging driver. Load: dtoverlay=sh1106-spi,= Params: speed SPI bus speed (default 4000000) rotate Display rotation (0, 90, 180 or 270; default 0) fps Delay between frame updates (default 25) debug Debug output level (0-7; default 0) dc_pin GPIO pin for D/C (default 24) reset_pin GPIO pin for RESET (default 25) height Display height (32 or 64; default 64) Name: smi Info: Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25! Load: dtoverlay=smi Params: Name: smi-dev Info: Enables the userspace interface for the SMI driver Load: dtoverlay=smi-dev Params: Name: smi-nand Info: Enables access to NAND flash via the SMI interface Load: dtoverlay=smi-nand Params: Name: spi-gpio35-39 Info: Move SPI function block to GPIO 35 to 39 Load: dtoverlay=spi-gpio35-39 Params: Name: spi-gpio40-45 Info: Move SPI function block to GPIOs 40 to 45 Load: dtoverlay=spi-gpio40-45 Params: Name: spi-rtc Info: Adds support for a number of SPI Real Time Clock devices Load: dtoverlay=spi-rtc,= Params: pcf2123 Select the PCF2123 device Name: spi0-cs Info: Allows the (software) CS pins for SPI0 to be changed Load: dtoverlay=spi0-cs,= Params: cs0_pin GPIO pin for CS0 (default 8) cs1_pin GPIO pin for CS1 (default 7) Name: spi0-hw-cs Info: Re-enables hardware CS/CE (chip selects) for SPI0 Load: dtoverlay=spi0-hw-cs Params: Name: spi1-1cs Info: Enables spi1 with a single chip select (CS) line and associated spidev dev node. The gpio pin number for the CS line and spidev device node creation are configurable. N.B.: spi1 is only accessible on devices with a 40pin header, eg: A+, B+, Zero and PI2 B; as well as the Compute Module. Load: dtoverlay=spi1-1cs,= Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.0 (default is 'okay' or enabled). Name: spi1-2cs Info: Enables spi1 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. N.B.: spi1 is only accessible on devices with a 40pin header, eg: A+, B+, Zero and PI2 B; as well as the Compute Module. Load: dtoverlay=spi1-2cs,= Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0). cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.0 (default is 'okay' or enabled). cs1_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.1 (default is 'okay' or enabled). Name: spi1-3cs Info: Enables spi1 with three chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. N.B.: spi1 is only accessible on devices with a 40pin header, eg: A+, B+, Zero and PI2 B; as well as the Compute Module. Load: dtoverlay=spi1-3cs,= Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0). cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1). cs2_pin GPIO pin for CS2 (default 16 - BCM SPI1_CE2). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.0 (default is 'okay' or enabled). cs1_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.1 (default is 'okay' or enabled). cs2_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev1.2 (default is 'okay' or enabled). Name: spi2-1cs Info: Enables spi2 with a single chip select (CS) line and associated spidev dev node. The gpio pin number for the CS line and spidev device node creation are configurable. N.B.: spi2 is only accessible with the Compute Module. Load: dtoverlay=spi2-1cs,= Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.0 (default is 'okay' or enabled). Name: spi2-2cs Info: Enables spi2 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. N.B.: spi2 is only accessible with the Compute Module. Load: dtoverlay=spi2-2cs,= Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0). cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.0 (default is 'okay' or enabled). cs1_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.1 (default is 'okay' or enabled). Name: spi2-3cs Info: Enables spi2 with three chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. N.B.: spi2 is only accessible with the Compute Module. Load: dtoverlay=spi2-3cs,= Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0). cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1). cs2_pin GPIO pin for CS2 (default 45 - BCM SPI2_CE2). cs0_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.0 (default is 'okay' or enabled). cs1_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.1 (default is 'okay' or enabled). cs2_spidev Set to 'disabled' to stop the creation of a userspace device node /dev/spidev2.2 (default is 'okay' or enabled). Name: spi3-1cs Info: Enables spi3 with a single chip select (CS) line and associated spidev dev node. The gpio pin number for the CS line and spidev device node creation are configurable. Load: dtoverlay=spi3-1cs,= Params: cs0_pin GPIO pin for CS0 (default 0 - BCM SPI3_CE0). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev3.0 (default is 'on' or enabled). Name: spi3-2cs Info: Enables spi3 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. Load: dtoverlay=spi3-2cs,= Params: cs0_pin GPIO pin for CS0 (default 0 - BCM SPI3_CE0). cs1_pin GPIO pin for CS1 (default 24 - BCM SPI3_CE1). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev3.0 (default is 'on' or enabled). cs1_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev3.1 (default is 'on' or enabled). Name: spi4-1cs Info: Enables spi4 with a single chip select (CS) line and associated spidev dev node. The gpio pin number for the CS line and spidev device node creation are configurable. Load: dtoverlay=spi4-1cs,= Params: cs0_pin GPIO pin for CS0 (default 4 - BCM SPI4_CE0). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev4.0 (default is 'on' or enabled). Name: spi4-2cs Info: Enables spi4 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. Load: dtoverlay=spi4-2cs,= Params: cs0_pin GPIO pin for CS0 (default 4 - BCM SPI4_CE0). cs1_pin GPIO pin for CS1 (default 25 - BCM SPI4_CE1). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev4.0 (default is 'on' or enabled). cs1_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev4.1 (default is 'on' or enabled). Name: spi5-1cs Info: Enables spi5 with a single chip select (CS) line and associated spidev dev node. The gpio pin numbers for the CS lines and spidev device node creation are configurable. Load: dtoverlay=spi5-1cs,= Params: cs0_pin GPIO pin for CS0 (default 12 - BCM SPI5_CE0). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev5.0 (default is 'on' or enabled). Name: spi5-2cs Info: Enables spi5 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. Load: dtoverlay=spi5-2cs,= Params: cs0_pin GPIO pin for CS0 (default 12 - BCM SPI5_CE0). cs1_pin GPIO pin for CS1 (default 26 - BCM SPI5_CE1). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev5.0 (default is 'on' or enabled). cs1_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev5.1 (default is 'on' or enabled). Name: spi6-1cs Info: Enables spi6 with a single chip select (CS) line and associated spidev dev node. The gpio pin number for the CS line and spidev device node creation are configurable. Load: dtoverlay=spi6-1cs,= Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI6_CE0). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev6.0 (default is 'on' or enabled). Name: spi6-2cs Info: Enables spi6 with two chip select (CS) lines and associated spidev dev nodes. The gpio pin numbers for the CS lines and spidev device node creation are configurable. Load: dtoverlay=spi6-2cs,= Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI6_CE0). cs1_pin GPIO pin for CS1 (default 27 - BCM SPI6_CE1). cs0_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev6.0 (default is 'on' or enabled). cs1_spidev Set to 'off' to prevent the creation of a userspace device node /dev/spidev6.1 (default is 'on' or enabled). Name: ssd1306 Info: Overlay for activation of SSD1306 over I2C OLED display framebuffer. Load: dtoverlay=ssd1306,= Params: address Location in display memory of first character. (default=0) width Width of display. (default=128) height Height of display. (default=64) offset virtual channel a. (default=0) normal Has no effect on displays tested. (default=not set) sequential Set this if every other scan line is missing. (default=not set) remapped Set this if display is garbled. (default=not set) inverted Set this if display is inverted and mirrored. (default=not set) Examples: Typical usage for 128x64 display: dtoverlay=ssd1306,inverted Typical usage for 128x32 display: dtoverlay=ssd1306,inverted,sequential i2c_baudrate=400000 will speed up the display. i2c_baudrate=1000000 seems to work even though it's not officially supported by the hardware, and is faster still. For more information refer to the device datasheet at: https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf Name: ssd1306-spi Info: Overlay for SSD1306 OLED via SPI using fbtft staging driver. Load: dtoverlay=ssd1306-spi,= Params: speed SPI bus speed (default 10000000) rotate Display rotation (0, 90, 180 or 270; default 0) fps Delay between frame updates (default 25) debug Debug output level (0-7; default 0) dc_pin GPIO pin for D/C (default 24) reset_pin GPIO pin for RESET (default 25) height Display height (32 or 64; default 64) Name: ssd1351-spi Info: Overlay for SSD1351 OLED via SPI using fbtft staging driver. Load: dtoverlay=ssd1351-spi,= Params: speed SPI bus speed (default 4500000) rotate Display rotation (0, 90, 180 or 270; default 0) fps Delay between frame updates (default 25) debug Debug output level (0-7; default 0) dc_pin GPIO pin for D/C (default 24) reset_pin GPIO pin for RESET (default 25) Name: superaudioboard Info: Configures the SuperAudioBoard sound card Load: dtoverlay=superaudioboard,= Params: gpiopin GPIO pin for codec reset Name: sx150x Info: Configures the Semtech SX150X I2C GPIO expanders. Load: dtoverlay=sx150x,= Params: sx150-- Enables SX150X device on I2C# with slave address . may be 1-9. may be 0 or 1. Permissible values of (which is denoted in hex) depend on the device variant. For SX1501, SX1502, SX1504 and SX1505, may be 20 or 21. For SX1503 and SX1506, may be 20. For SX1507 and SX1509, may be 3E, 3F, 70 or 71. For SX1508, may be 20, 21, 22 or 23. sx150---int-gpio Integer, enables interrupts on SX150X device on I2C# with slave address , specifies the GPIO pin to which NINT output of SX150X is connected. Name: tc358743 Info: Toshiba TC358743 HDMI to CSI-2 bridge chip. Uses Unicam 1, which is the standard camera connector on most Pi variants. Load: dtoverlay=tc358743,= Params: 4lane Use 4 lanes (only applicable to Compute Modules CAM1 connector). link-frequency Set the link frequency. Only values of 297000000 (574Mbit/s) and 486000000 (972Mbit/s - default) are supported by the driver. i2c_pins_0_1 Use pins 0&1 for the I2C instead of 44&45. Useful on Compute Modules. i2c_pins_28_29 Use pins 28&29 for the I2C instead of 44&45. This is required for Pi B+, 2, 0, and 0W. Name: tc358743-audio Info: Used in combination with the tc358743-fast overlay to route the audio from the TC358743 over I2S to the Pi. Wiring is LRCK/WFS to GPIO 19, BCK/SCK to GPIO 18, and DATA/SD to GPIO 20. Load: dtoverlay=tc358743-audio,= Params: card-name Override the default, "tc358743", card name. Name: tinylcd35 Info: 3.5" Color TFT Display by www.tinylcd.com Options: Touch, RTC, keypad Load: dtoverlay=tinylcd35,= Params: speed Display SPI bus speed rotate Display rotation {0,90,180,270} fps Delay between frame updates debug Debug output level {0-7} touch Enable touch panel touchgpio Touch controller IRQ GPIO xohms Touchpanel: Resistance of X-plate in ohms rtc-pcf PCF8563 Real Time Clock rtc-ds DS1307 Real Time Clock keypad Enable keypad Examples: Display with touchpanel, PCF8563 RTC and keypad: dtoverlay=tinylcd35,touch,rtc-pcf,keypad Old touch display: dtoverlay=tinylcd35,touch,touchgpio=3 Name: tpm-slb9670 Info: Enables support for Infineon SLB9670 Trusted Platform Module add-on boards, which can be used as a secure key storage and hwrng, available as "Iridium SLB9670" by Infineon and "LetsTrust TPM" by pi3g. Load: dtoverlay=tpm-slb9670 Params: Name: uart0 Info: Change the pin usage of uart0 Load: dtoverlay=uart0,= Params: txd0_pin GPIO pin for TXD0 (14, 32 or 36 - default 14) rxd0_pin GPIO pin for RXD0 (15, 33 or 37 - default 15) pin_func Alternative pin function - 4(Alt0) for 14&15, 7(Alt3) for 32&33, 6(Alt2) for 36&37 Name: uart1 Info: Change the pin usage of uart1 Load: dtoverlay=uart1,= Params: txd1_pin GPIO pin for TXD1 (14, 32 or 40 - default 14) rxd1_pin GPIO pin for RXD1 (15, 33 or 41 - default 15) Name: uart2 Info: Enable uart 2 on GPIOs 0-3 Load: dtoverlay=uart2, Params: ctsrts Enable CTS/RTS on GPIOs 2-3 (default off) Name: uart3 Info: Enable uart 3 on GPIOs 4-7 Load: dtoverlay=uart3, Params: ctsrts Enable CTS/RTS on GPIOs 6-7 (default off) Name: uart4 Info: Enable uart 4 on GPIOs 8-11 Load: dtoverlay=uart4, Params: ctsrts Enable CTS/RTS on GPIOs 10-11 (default off) Name: uart5 Info: Enable uart 5 on GPIOs 12-15 Load: dtoverlay=uart5, Params: ctsrts Enable CTS/RTS on GPIOs 14-15 (default off) Name: udrc Info: Configures the NW Digital Radio UDRC Hat Load: dtoverlay=udrc,= Params: alsaname Name of the ALSA audio device (default "udrc") Name: upstream Info: Allow usage of downstream .dtb with upstream kernel. Comprises the vc4-kms-v3d and dwc2 overlays. Load: dtoverlay=upstream Params: Name: upstream-aux-interrupt Info: This overlay has been deprecated and removed because it is no longer necessary. Load: Name: vc4-fkms-v3d Info: Enable Eric Anholt's DRM VC4 V3D driver on top of the dispmanx display stack. Load: dtoverlay=vc4-fkms-v3d, Params: cma-256 CMA is 256MB (needs 1GB) cma-192 CMA is 192MB (needs 1GB) cma-128 CMA is 128MB cma-96 CMA is 96MB cma-64 CMA is 64MB Name: vc4-kms-kippah-7inch Info: Enable the Adafruit DPI Kippah with the 7" Ontat panel attached. Requires vc4-kms-v3d to be loaded. Load: dtoverlay=vc4-kms-kippah-7inch Params: Name: vc4-kms-v3d Info: Enable Eric Anholt's DRM VC4 HDMI/HVS/V3D driver. Running startx or booting to GUI while this overlay is in use will cause interesting lockups. Load: dtoverlay=vc4-kms-v3d, Params: cma-256 CMA is 256MB (needs 1GB) cma-192 CMA is 192MB (needs 1GB) cma-128 CMA is 128MB cma-96 CMA is 96MB cma-64 CMA is 64MB audio Enable or disable audio over HDMI (default "on") Name: vga666 Info: Overlay for the Fen Logic VGA666 board This uses GPIOs 2-21 (so no I2C), and activates the output 2-3 seconds after the kernel has started. Load: dtoverlay=vga666 Params: Name: w1-gpio Info: Configures the w1-gpio Onewire interface module. Use this overlay if you *don't* need a GPIO to drive an external pullup. Load: dtoverlay=w1-gpio,= Params: gpiopin GPIO for I/O (default "4") pullup Now enabled by default (ignored) Name: w1-gpio-pullup Info: Configures the w1-gpio Onewire interface module. Use this overlay if you *do* need a GPIO to drive an external pullup. Load: dtoverlay=w1-gpio-pullup,= Params: gpiopin GPIO for I/O (default "4") extpullup GPIO for external pullup (default "5") pullup Now enabled by default (ignored) Name: w5500 Info: Overlay for the Wiznet W5500 Ethernet Controller on SPI0 Load: dtoverlay=w5500,= Params: int_pin GPIO used for INT (default 25) speed SPI bus speed (default 30000000) cs SPI bus Chip Select (default 0) Name: wittypi Info: Configures the wittypi RTC module. Load: dtoverlay=wittypi,= Params: led_gpio GPIO for LED (default "17") led_trigger Choose which activity the LED tracks (default "default-on") Troubleshooting =============== If you are experiencing problems that you think are DT-related, enable DT diagnostic output by adding this to /boot/config.txt: dtdebug=on and rebooting. Then run: sudo vcdbg log msg and look for relevant messages. Further reading =============== This is only meant to be a quick introduction to the subject of Device Tree on Raspberry Pi. There is a more complete explanation here: http://www.raspberrypi.org/documentation/configuration/device-tree.md