How to enable SPI on the BeagleY-AI

Hardware and Software Requirements

This article documents how to enable hardware SPI on the BeagleY-AI.

By default, the board ships with a bit-banged SPI implementation, and the spidev device is not exposed under /dev/spidevX.Y, preventing user-space applications from accessing the SPI controller.

Considering how new the BeagleY-AI platform is, documentation is still limited. During research, the following references were particularly helpful:

Kernel and Boot Context

Host OS: Debian 6.1.158-1 (x86_64)
Target kernel: 6.1.83-ti-arm64-r72+
Kernel built from source and deployed to SD card
Custom DTBO compiled and passed to the kernel
Boot configuration handled via extlinux.conf

Clone DTS File from Source

Clone the repository containing the DTS file required to enable SPI:

cd ~
git clone https://github.com/wcs3/BYAI-mcu_spi0.git
cd BYAI-mcu_spi0

Compile DTS File to DTBO

NB: Ensure the following include paths are available to the device tree compiler:

arch/arm64/boot/dts
arch/arm64/boot/dts/ti

Once inside the kernel source tree, compile the DTBO using:

cpp -nostdinc -I include -I arch/arm64/boot/dts \ -I arch/arm64/boot/dts/ti -undef -x assembler-with-cpp \ arch/arm64/boot/dts/ti/k3-am67a-beagley-ai-spidev0-mcu.dts | dtc -@ -I dts -O dtb -o k3-am67a-beagley-ai-spidev0-mcu.dtbo

If successful, the output file k3-am67a-beagley-ai-spidev0-mcu.dtbo will be generated and ready for deployment.

Deploy to the Board

Copy the compiled DTBO to the SD card and update the boot configuration:

cp k3-am67a-beagley-ai-spidev0-mcu.dtbo /media/user/BOOT/overlays
sync
ls /media/user/BOOT/overlays
nano /media/user/BOOT/extlinux/extlinux.conf
Add: fdtoverlays /overlays/k3-am67a-beagley-ai-spidev0-mcu.dtbo under the default boot entry
sudo umount /media/user/BOOT
sudo umount /media/user/rootfs

Test the Driver

After reinserting the SD card and booting the BeagleY-AI, observe the UART console for SPI initialization messages.

UART console output showing SPI driver initialization — UART console output during SPI driver initialization

Once the system has booted, verify that the SPI device node is present:

spidev device visible under /dev — SPI device exposed under /dev as spidev

This article is shared freely to assist others working with the BeagleY-AI platform.