“USB host/device implementation using PIO of raspberry pi pico (RP2040).
You can add additional USB port to RP2040.
- Two PIO
- One PIO is for USB transmitter using 22 instruction and one state machine
- Another PIO is for USB receiver using 31 instruction and two state machine
- Two GPIO for D+/D- (Series 22ohm resitors are better)
- 15KB ROM and RAM
- (For Host) One 1ms repeating timer
- (For Device) One PIO IRQ for receiver”