Are Le Potatoes GPIO board compatible with the GPIO on the Raspberry Pi 3B+?. I would like to switch to Le Potato boards for audio HAT projects that I build using PiCore Player and preferably HiFiBerry Amp and DAC boards.
Thanks for your help.
No, those use PCM and I2S pin mux that are not the same
That’s a bit unfortunate since I discovered just yesterday that the Le Potato board works beautifully with Roon while driving an external USB DAC (more details here). Are any of the other Libre Computer boards fully GPIO compatible with the Raspberry Pi? If not, are there any 3rd parties that are making HAT boards that are pin-compatible with the LIbre Computer GPIO system? I’m not a hardware expert, but from the AML-S905X-CC-V1.0A Headers reference, I see enough digital audio I/O pins there to imagine that DAC, ADC, and digital I/O HAT integration would be possible.
Regardless, I’m delighted that this board (and others from Libre Computer) are now available at such affordable prices. I know I’ll enjoy using them based on my first experience with Le Potato. Thanks.
No, pin multiplexing is different on every SoC. Even Raspberry Pi does not maintain exact pinmux across its entire family.
I wonder how HAT manufacturers deal with this problem in the Raspberry Pi line. Is this something that they can work around?
BTW, here are the pins for the PecanPi/PecanPi+ DAC HATs from Orchard Audio:
They release per board HATs. Eg. For Pi 1/2, 3/4 as separate boards. Most of these boards use either PCM audio or I2S audio. PCM is used by TosLink/SPDIF and I2S is used by HDMI among others.
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It looks like the i2s pins on the Tritium H3/H5 do match up with the Pi 3/4. I think this means you could use a GPIO sound card (e.g. Hifiberry) on the Tritium as long as someone writes an appropriate dtoverlay as described in this post, or could one just use the same dtoverlay as for the Pi 3/4?
Raspberry Pi overlays will not work with any other board. They should be used as a reference for the clock, interrupt, and GPIO setup but definitely not copied verbatim since the GPIO, clock, and interrupts are different.
Just because I2S matches up does not mean they can support the same configuration as on the Raspberry Pi. See linux-sunxi for more information on H5 I2S.
Update: It looks like I2S is not supported upstream: Linux mainlining effort - linux-sunxi.org