passthru.go

package main

import (
	"machine"
	"time"
)

var (
	nina = machine.UART1
	tx   = machine.PA22
	rx   = machine.PA23

	usb = machine.UART0

	reset = machine.NINA_RESETN
	gpio0 = machine.NINA_GPIO0
)

func main() {
	led := machine.LED
	led.Configure(machine.PinConfig{Mode: machine.PinOutput})
	led.Low()

	nina.Configure(machine.UARTConfig{TX: tx, RX: rx})

	// switch to load bootloader
	gpio0.Configure(machine.PinConfig{Mode: machine.PinOutput})
	reset.Configure(machine.PinConfig{Mode: machine.PinOutput})

	gpio0.Low()
	reset.Low()
	time.Sleep(100 * time.Millisecond)

	reset.High()
	time.Sleep(100 * time.Millisecond)

	for {
		for usb.Buffered() > 0 {
			data, _ := usb.ReadByte()
			nina.WriteByte(data)
		}

		for nina.Buffered() > 0 {
			data, _ := nina.ReadByte()
			usb.WriteByte(data)
		}
	}
}