On of my ongoing issues is getting data out - UART time:
from machine import UART, Pin
uart0 = UART(0, baudrate=115200, tx=Pin(0), rx=Pin(1))
uart1 = UART(1, baudrate=115200, tx=Pin(8), rx=Pin(9))
tx = bytearray(range(256))
uart1.write(tx)
rx = bytearray(256)
nn = uart0.readinto(rx)
assert nn == 256
for j in range(256):
assert tx[j] == rx[j]