MicroPython Forum (Archive)

Code: Select all

from pyb import Pin, Timer
from time import ticks_diff, ticks_us
import micropython

p = Pin('X1')
tim = Timer(2, freq=38000)
ch = tim.channel(1, Timer.PWM, pin=p)
ch.pulse_width_percent(50)

def wait(bit):
    tw = 1687 if bit else 563
    t = ticks_us()
    while ticks_diff(ticks_us(), t) < tw:
        pass

def send(bit):
    ch.pulse_width_percent(50)
    wait(1)
    ch.pulse_width_percent(0)
    wait(bit)

def test():
    while True:
        for bit in [1,0,1,1,0]:
            send(bit)

Code: Select all

from pyb import Pin, Timer
from time import sleep_us, sleep
from micropython import const

_SPACE = const(0)  # Or 100 depending on wiring
_TBURST = const(563)
_T_ONE = const(1687)
_TSTART = const(9000)

p = Pin('X1')
tim = Timer(2, freq=38000)
ch = tim.channel(1, Timer.PWM, pin=p)
ch.pulse_width_percent(_SPACE)

def send(bit):
    ch.pulse_width_percent(50)
    sleep_us(_TBURST)
    ch.pulse_width_percent(_SPACE)
    sleep_us(_T_ONE if bit else _TBURST)

def sendbyte(b):  # Send byte followed by 1's complement
    for x in range(8):
        send((b >> x) & 1)
    b ^= 0xff
    for x in range(8):
        send((b >> x) & 1)

# Send preamble, address, data, stop
def transmit(addr, data):
    ch.pulse_width_percent(50)  # Start
    sleep_us(_TSTART)
    ch.pulse_width_percent(_SPACE)
    sleep_us(4500)
    sendbyte(addr)  # Now send address and data
    sendbyte(data)
    ch.pulse_width_percent(50)
    sleep_us(_TBURST)
    ch.pulse_width_percent(_SPACE)

# Repeat code sent when a button is held down.
# Send 108 ms after transmit start, optionally again at 108ms intervals
def repeat():
    ch.pulse_width_percent(50)
    sleep_us(_TSTART)
    ch.pulse_width_percent(_SPACE)
    sleep_us(2250)
    ch.pulse_width_percent(50)
    sleep_us(_TBURST)
    ch.pulse_width_percent(_SPACE)

def test():
    while True:
        transmit(0, 0xad)
        sleep(1)