AML-S905X-CC Wiring Tool Overlays Description

[librecomputer]

This is a list of device tree overlays provided by the Libre Computer Wiring Tool and what they do.

If this document is not up to date, please let us know.

• i2c-ao.dts - i2c ao on pin 3 and 5
• i2c-ao-ds3231.dts - ds3231 attached to i2c ao
• i2c-ao-at24c32.dts - at24c32 attached to i2c ao
• i2c-b.dts - i2c b on pin 27 and 28 (RPI HAT EEPROM pins)
• i2c-b-at24c32.dts - at24c32 attached to i2c b
• i2c-b-ds3231.dts - ds3231 attached to i2c b
• pwm-e.dts - pwm e on pin 32
• rpi-sense.dts - RPI Sense HAT
• sdio.dts - sdio overlay for WiFi/BT
• spicc-cs1.dts - spi cc on pin 19, 21, 23 with 24 26 chip enable
• spicc-cs1-spidev.dts - spi cc with userspace spidev0.0 and spidev0.1
• spicc.dts - spi cc on pin 19, 21, 23 with 24 chip enable
• spicc-spidev.dts - spi cc with userspace spidev0.0
• spigpio-cs1.dts - software spi on pin 19, 21, 23 with 24 26 chip enable
• spigpio-cs1-spidev.dts - software spi with userspace spidev0.0 and spidev0.1
• uarta.dts - uart a on pin 8 and 10 with flow control on pin 16 and 18

There are a lot more functionality not exposed in which you have to write your own overlay. These serve as simple references for you to get started with.

[Oscar_Sanchez]

so by activating spicc.dts the spi pin 19-21-23-24 on the 40 pin should work just like it does on rpi?

[librecomputer]

@Oscar_Sanchez

21

Raspberry Pi SPI is usually the spicc-cs dtbo where /dev/spidev0.0 is enabled by pin 24 and /dev/spidev0.1 is enabled by pin 26. You can use the ./spidev-setup cs1

[Oscar_Sanchez]

If using the new raspbian distro image, would you still need to run the wiring tool and activate the right SPI to have the same pin layout and usage as the pi?

[librecomputer]

Yes, Raspberry Pi depend on the bootloader to read config.txt. Our bootloader does not read it at all. We are exploring creating a service to do it but that’s still in the conceptual stage at this point.