Pdm microphone mystery I was puzzled that ESP-IDF’s PDM I2S config has no LR pin—until I actually read the mic’s datasheet. On PDM mics, LR isn’t a word-select clock at all; it picks which clock edge the mic drives and tri-states on the opposite edge. Tie one mic’s LR low and the other high and both share the same data line for stereo—no extra GPIO needed. I scoped it with some nice pogo probes to confirm, and it matches the timing diagrams perfectly. Net win: one fewer pin in the next design. 10 October 2025