Embedded & hardware
PARLIO Audio TX
I2S, TDM, ADAT and S/PDIF — all from one peripheral.
An ESP32-P4 audio transmitter that creatively repurposes the parallel-IO peripheral as a deep multi-protocol digital audio output. APLL drives the I2S MCLK, the same GPIO is fed back into PARLIO as an external clock, and DMA buffers shift out pre-encoded bit patterns on 16 parallel data lines — synthesizing I2S, TDM-8/16, ADAT and S/PDIF in software.
Specifications
- Three peripherals chained: APLL → I2S MCLK → GPIO matrix → PARLIO
- 16 parallel TXD lines, sample-accurate via DMA
- Encodes I2S Philips, TDM-8 / TDM-16, ADAT and S/PDIF biphase
- Native 44.1 / 48 / 88.2 / 96 kHz from the audio PLL
- No CPU involvement on the hot path, no jitter
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