vx7read.py

#!/usr/bin/python
import sys, os, serial, time
DEV = '/dev'
PORTS = [os.path.join(DEV, port) for port in os.listdir(DEV)
 if port.startswith('ttyUSB')]
ACK = chr(6)
DATASIZE = 16211
def read(port, count, checksum = False):
 debug('attempting to read %d bytes from %s' % (count, port))
 data = port.read(count)
 debug('%d bytes of data read: %s' % (len(data), data[:40].encode('hex')))
 if not checksum:
  time.sleep(0.2)  # delay before ACK
  port.write(ACK)
  ack = port.read(1)
  if not ack == ACK:
   print >>sys.stderr, '%s seen when ACK (%s) expected' % (repr(ack), repr(ACK))
   sys.exit(1)
 return data
def write(filename, data):
 if filename is None:
  if sys.stdin.isatty():
   print data.encode('hex')
  else:
   sys.stdout.write(data)
 else:
  outfile = open(filename, 'wb')
  outfile.write(data)
  outfile.close()
def debug(message):
 if __debug__:
  if message:
   print >>sys.stderr, message
def comm(filename = None, port = None):
 port = serial.Serial(port or PORTS[0], baudrate = 19200,
  stopbits = 2, timeout = 20)
 port.flushInput()
 raw_input('''Instructions:
  1) While holding MON-F, power on VX-7R
  2) Hit <Enter> on computer keyboard
  3) Within 30 seconds, hit BAND key on VX-7R ''')
 data = read(port, 10)
 data += read(port, 8)
 data += read(port, DATASIZE - 10 - 8, checksum = True)
 port.close()
 write(filename, data)
if __name__ == '__main__':
 comm(*sys.argv[1:])