AI-64 Pinmuxing with MiniDisplayPort

Hi! In the Beaglebone Black Wireless, when a screen was connected via the HDMI, much of the P8 header pins were unusable as they were used by the screen. The Beaglebone AI-64 has a different connector, miniDisplayPort, 2x 4-lane CSI, DSI, so I’m wondering if I’ll have the same situation here. I’d like to use a screen while also using some pins for my own purposes, such as UART 5 (P8 37,38)

Can anyone shed some light?

Does anyone have a link to information about pinmuxing assignments for all interfaces and PRU processors?

Hello @beagleflyer ,

These are the docs. so far: / beaglebone-ai-64 · GitLab


P.S. It may take some time for people to test everything to make sure things are working and available to the public. FYI, I am staying patient right now in case I do something that is incorrect.

Hi Seth, can you point me to the location of the docs regarding pinmuxing? Perhaps a pinout table or something? I can’t find it there. Surely it’s not missing, as I don’t see how people can develop against the pins without it?


I think using this, src/arm64/k3-j721e-beagleboneai64.dts · bbai64 · / BeagleBoard-DeviceTrees · GitLab , could shed some light but it is not fully compatible as of now.

I say test each pin w/ an oscilloscope along w/ that .dts file could benefit here and other users.


P.S. Also, there is a file, the TRM, for the processor. This will come in handy. Here:

So, if you find that the GPIO registers in the file are located as such, then you have found the GPIO register mapping already. Anyway, philosophy-blah, Registers4 is where you can find GPIO, UART, and I2C registers on the core(s). It will be more complicated to map and find what is exactly what currently, e.g. this may change in the future also.

You can check the schematic for the header pins. It list some of the functions of the pins, but not all I think. It does list the chip PAD numbers.

If you download the tda4vm.pdf from Ti, it lists all of the pads and all of the modes for those pins. You will need the muxmode if you plan on changing the DTS file,

There are macros for all of the header pins to set the mux mode.
Note many of the header pins are actually connected to 2 pads on the chip. If you use these you need to make sure the unused pad is set to something safe. Probably GPIO input.

I have not managed to get an overlay DTS file working, so have just edited the main DTS file to enable the functions I need.

1 Like