Prompt for SCPI over USB

scpi_over_usb.py

"""
Script for issuing SCPI commands over USB. Slightly nicer to use than `echo "RCL5" > /dev/ttyACM0`.

Author: J. L. Hay
"""


from select import select
from time import sleep


POWER_SUPPLY_FILEPATH = "/dev/ttyACM0"
POWER_SUPPLY_FILE_W = open(POWER_SUPPLY_FILEPATH, "w")
POWER_SUPPLY_FILE_R = open(POWER_SUPPLY_FILEPATH, "r")

PROMPT = ">>> "


def main():

    while (user_input := input(PROMPT)) != None:
        POWER_SUPPLY_FILE_W.write(user_input + "\n")
        sleep(0.1)
        can_read, _, _ = select([POWER_SUPPLY_FILE_R], [], [], 0)
        if can_read:
            print(POWER_SUPPLY_FILE_R.readline().strip())


if __name__ == "__main__":

    try:
        main()
    except KeyboardInterrupt:
        POWER_SUPPLY_FILE_W.close()
        POWER_SUPPLY_FILE_R.close()
        print("")