QA402/403 I2S expansion specifications


I have the pin-out of the expansion header, but couldn’t find the documentation for the pins in the header, i.e. max speed, io-levels etc.

Also, would it be possible to add support for TDM8 and TDM16?

Thx David

Hi @audio-dav, the pinout is listed at the link below. That covers the pin names and nominal voltages and currents you might expect from the supply. In most cases, you’d go to an isolator and on the other side of the isolator use whatever voltage you want. See the picture in the wiki link.

Right now, the choices are 16 or 32-bit words and its fixed at 48K. There’s more programmability that could be had here, but we’d need someone to champion it and verify it. Ideally someone would have a new piece of hardware they need to get working (that the QA403 will be testing in manufacturing) and that’s a good way to get the support added and verified. I think the hardware (LPC55S16) can do the TDM. You might take a look through the LPC55S16 spec and see what it can do, and we could probably add that it. For example, for TDM I think we could add a way to specify a slot, but I don’t think we could add a way to have, say, 8 independent channels of data over a TDM8 packet.

What are you thinking?

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thanks for the link matt,

LPC55x can do TDM and it’s possible to run 8ch per data pin.
no stress to implement this, we played with the idea and might need it to feed a board that has an 8ch (ESS) DAC that would be nice to feed directly via TDM, 1-2 channels at the time to avoid the need for relay boxes or i2s muxes.