I’ve started to explore a topic to turn VIM3/VIM3L into powerful signal processor as seems that SBC and Amlogic chip is much better suited for that rather then Raspberry PI4 due onboard NPU and built-in audio-codec.
And it would be much appreciated if you can give some answers and guidance on that long way.
From my perspective if I could make NPU to run the same - it would be really great.
But the target is a bit difficult to reach as there are some steps needs to be taken
1/ Adopt Xenomai and Elk audio project (realtime linux microkernel ) to Amlogic chip
2/ Adapt Amlogic audio drivers to RTDM (realtime driver model) in Xenomai taking other as example - https://github.com/elk-audio/rpi-rtdm-audio-driver
3/ Attach some ADC/DAC hardware to I2S bus.
So to just explore possibilities without going into much HW changes - I’m planning to tryout SPDIF IN/OUT ports on VIM3/L SBC and luckily all that available on 40 pin header
SPDIF out is already there, but for SPDIF I wanted to change PWM_F pin into SPDIF IN - could you please let me know what needs to be changed (u-boot, dts, smth else) to change this pin into SPDIF mode ?
Also there is a DAC already on board
Does it only work in balanced mode or can be switched to unbalanced ? Do I need just to get an output signal from TP(3-6) pinounts on a board ?
More questions will follow…
Many thanks in advance