SR830 repl.

sr830_repl.py

#!/usr/bin/env python
# encoding: utf-8

"""
Usage:

rlwrap ./srs_test.py
"""

import os
from serial import Serial


def connect(path=None):
    if path is None:
        ports = list(filter(lambda f: 'ttyUSB' in f, os.listdir('/dev')))
        if not ports:
            raise Exception("No serial connection detected")
        path = '/dev/' + ports[0]
    return Serial(path, baudrate=9600, timeout=1)


def test_connection(ser):
    ser.write('*idn?\n')
    line = readuntil(ser, '\r')
    print line
    return line.startswith('Stanford_Research_Systems')


def send_command(ser, command, output=False):
    ser.write(command + '\n')
    if output:
        return readuntil(ser, '\r')


def readuntil(ser, ch):
    buf = ser.read(1)
    if not buf:
        return buf
    while buf[-1] != ch:
        buf += ser.read(1)
    return buf


def repl(ser):
    while True:
        print '>>>',
        try:
            cmd = raw_input()
        except EOFError:
            exit()
        output = send_command(ser, cmd, '?' in cmd)
        if output:
            print output

if __name__ == '__main__':
    ser = connect()
    print 'Testing connection...'
    assert test_connection(ser)
    print 'Starting REPL...'
    repl(ser)