aml.py

#!/usr/bin/env python

import time, serial

"""
This is the AML object the controls communication between
the computer and the AML stepper motor driver.
"""
class AML(object):
    
    def __init__(self, port='/dev/tty.USA19H1461P1.1'):
        self.port = port
        self.connected = False
        self.start_serial(self.port)


    #Open a port for serial communication. 
    def start_serial(self, port):
        # Configure the serial connections 
        # These are specific to the AML SMD2 Stepper Controller
        try:
            self.ser = serial.Serial(
                    port=port,
                    baudrate=9600,
                    parity=serial.PARITY_ODD,
                    bytesize=serial.SEVENBITS,
                    stopbits=serial.STOPBITS_TWO
            )

            # Need to set the "request to send" pin low
            self.ser.setRTS(False)
            self.connected = True

            time.sleep(.25)
        except:
            print("Something went wrong connecting to AML serial...")
        
        
    def write(self, command):
        self.ser.write(command + '\r') # appending a \r, required by the SMD2
        time.sleep(.25) # .1 sec seems too fast, but maybe not...?
         
         
    def close_serial(self):
        self.ser.close()


    def read(self):
            out = []
            while self.ser.inWaiting() > 0:
                data = str(self.ser.read())
                if data == '\r':
                    out.append('\n')
                else:
                    out.append(data)
            if out != '':
                return ' '.join(out)
            else:
                return None


    def write_and_read(self, command):
        self.write(command)
        return self.read()