Hi
I have some SIM (Simcom) modules(various models) with PCM audio input and output (short sync pulse mode), and on the other side I have a ESP32 module with I2S ports.
I'm trying to connect the two without making it too complicated. I though about using the SPI in slave mode, but the short sync pulse can't be used as the CS signal, so that wont work.
Also I don't think the transmit side clock/data polarity would be correct.
All I can think about is putting in a little CPLD/FPGA to reformat the data, but that sounds as a bit of an overkill, and a MCU won't cut it since the data is too fast to bitbang.
I could do it in TTL, but at that point the logic would be so complex I might as well do it with a FPGA...
I found that there is a TI audio system IC in BGA, but that's too big and too complex for what I need here.
Does anyone have an idea for a simpler workaround?