autoreset

#!/usr/bin/python
"""
# Python script to check ioctl_tty for DTR send signal and toggle GPIO for avrdude.
#/usr/bin/autoreset
#
# #References:
# https://github.com/deanmao/avrdude-rpi
# https://github.com/mharizanov/avrdude-rpi
# https://github.com/SpellFoundry/avrdude-rpi
# https://github.com/openenergymonitor/avrdude-rpi
"""

import sys, os, time, fcntl
import RPi.GPIO as GPIO

## Configure ##
GPIO.setmode(GPIO.BOARD)
_RESET_PIN = 13 # BOARD: 13 = BCM: 27
_PULSE_TIME = 0.12  # Seconds
_TIMEOUT = 60  # Seconds


def set_stdin_to_nonblocking():
    """ Sets STDIN to be non-blocking """
    fd = sys.stdin.fileno()
    fl = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)


def send_reset_pulse(pin, pulse_time):
    """ Send reset pulse to MCU on reset line over GPIO pin """
    GPIO.setup(pin, GPIO.OUT)
    GPIO.output(pin, GPIO.HIGH)
    time.sleep(pulse_time)
    GPIO.output(pin, GPIO.LOW)


def process():
    """ Detects TIOCM_DTR call from ioctl_tty from STDIN """
    _DTR = "TIOCM_DTR"
    _IOCTL_CMD = "TIOCMGET"
    start = time.time()
    while True:
        duration = time.time() - start
        stdin_text = sys.stdin.readline()
        if _DTR in stdin_text:
            send_reset_pulse(_RESET_PIN, _PULSE_TIME)
            return
        elif duration > _TIMEOUT:
            return


if __name__ == "__main__":
    set_stdin_to_nonblocking()
    process()
    GPIO.cleanup()
    print("Done with autoreset")