Today I managed to connect the Digilent Pmod I2S2 to a Raspberry Pi 4 and have all frequencies generated. This is part of an older project that I left abandoned for a while: a radio node built on Raspberry Pi and using Svxlink. As known, Raspberry boards do not have a proper audio interface and I used in my previous node an USB audio dongle which is cumbersome and not elegant. So I wanted to explore the I2S interface of Raspberry. For more information regarding the hardware setup, there is extensive information on the internet and I will provide some links at the end of the article.
I used a Microchip DSC1001 1.8V-3.3V Low-Power Precision CMOS Oscillator for this prototype to generate 24.576 MHz frequency as required by both CS4344 and CS5343. The PMOD I2S2 is working in Master Mode. The signals were quite noisy due to the proto nature but also due to the scope probes that have too long ground wires that behave like antennas.
Raspberry Pi I2S interface proto v1-0 — the oscillator can be seen at the bottom in “dead bug” mode
Next article will cover in more details the hardware and in the third part I will hopefully manage to provide information regarding software.
Bye
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