4 ms·
Well yeah you don't need a DAC but that will eat a lot of CPU cycles
by raverbashing 3y ago
Well yeah you don't need a DAC but that will eat a lot of CPU cycles
- crote 3y agoUsually there are plenty of free unused CPU cycles. External hardware, on the other hand, is expensive. So why not save some money and use the CPU? Besides, I don't think it actually uses substantially more CPU than an external DAC. You'd be feeding a DMA buffer into the I2S peripheral either way. If you precompute the PDM waveform from the audio sample it's essentially free. Using a LUT or even computing it realtime should only take a dozen or so cycles per sample, at 44.1kHz. Considering that the ESP32-S3 has two cores running at 240MHz, even taking an excessive 500 cycles per sample would only be a 5% CPU load.
- dekhn 3y agoTo me the value of the ESP32 has always been the peripherals that substitute for pure CPU usage (although, it's certainly nice that it has the CPU cycles to do interesting things).
- iamflimflam1 3y agoYou feed in the PCM samples, the I2S peripheral handles the PDM in hardware. So no CPU should be used.
- dekhn 3y agoRead the comment I'm replying to.
- raverbashing 3y agoYou can't do much lookup with sigma-delta modulation but > has two cores running at 240MHz Yeah ok that is manageable.
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