# Alternate device tree Examples:
Each folder contains a `.dts` file and a README showing the GPIO pin mappings.

Copy the desired `.dts` file to the [build-trees](../build-trees) folder and follow the readme there to build the device-tree binaries.

There are instructions at the end of that document on how you can use a custom `.dtb` and make it permanent across reboots and kernel upgrades.

The issue with using these trees is that **if** the upstream device tree or includes is modified you need to manually rebuild these trees.

EG any changes to the upstream `sun20i-d1-mangopi-mq-pro.dts` source needs to be detected and applied too. You need to examine file histories to do this.
- Fortunately this should not be an issue in practice; the kernel *should* remain very stable going forward. Ubuntu 24.04.1 is a LTS release..

The authors personal advice is to use this only if needed; or as a learning excercise.

## SPI and I2C
[SPI plus I2C interfaces](./spi_i2c)
* 1x SPI
* 4x I2C
* 3x UART (plus the console uart)
* 6 unassigned GPIO pins

## Serial
[Four UART interfaces](./serial)
* 4x UART (plus the console uart)
  * UART3 has RTC/CTS pins available too
* 2x I2C
* 12 unassigned GPIO pins