Thread · HN Continuity

I’ve been developing a guitar pedal firmware in an ESP32-P4, and the flash image size is still under 1 MB and the PSRAM sits unused. It has not only a bunch of sound filters, control code for ADC, DAC a couple of USB devices, SDIO and LittleFS, but also a full-blown serial terminal TUI to control all sorts of details and to monitor performance. Said performance is good, but what blows me away is that there’s no jitter in the number that measures the number of cycles the processor executes while processing a sound frame, i.e. no preemption by the kernel to go and take care of its business.

There’s no way a multi-user OS such as Linux can be as efficient as a firmware blob that does one thing. Tell me if I’m wrong, but in my mental model, one can get about the same mileage with 16 MB of PSRAM in an MCU running FreeRTOS as one can get in a 512 MB SBC running Linux. For my use case, the winner combination would, of course, be a 512 MB SBC running FreeRTOS, but I’ve so far been unable to find such a wondrous thing.