As its name suggests, the Raspberry Pi RP2350 is optimized for PWM and offers ample GPIO, but what if you need more PWM channels?
One hacker has used a second RP2350 as a port expander to provide extra PWM, keeping the firmware on the main microcontroller and simply using the latter to reprogram the expander.
The main limitation is the 512 kB of RAM, but the hacker in question said this was ample for their requirements, and the UART bootloader does add a one-second boot delay.
The upshot is that is possible to reprogram the expander remotely using RS-485 and TI’s THVD1450, with a potential range of up to 1 km.
