#!/usr/bin/python
import sys, os, serial, time, re
DEV = '/dev'
PORTS = [os.path.join(DEV, port) for port in os.listdir(DEV)
 if port.startswith('ttyUSB')]
TIMEOUT = 0.2  # for serial communications
PAUSE = 0.1  # for hardware signaling
EOL = '\r\n'
TOGGLE_LINES = True
CLOCK_RATE = '20000'  # clock rate of SBC in KHz (CCLK) (as string)
CMD_SUCCESS = '0'  # expected from PCB after successful command entry
def dump(*args):
 if len(args) != 2:
  print >>sys.stderr, 'Must specify start address and number of bytes'
  sys.exit(1)
 start, bytecount = map(safeint, args)
 print >>sys.stderr, 'Dumping %d bytes starting at 0x%x' % (bytecount, start)
 port = init()
 sync(port)
 dumped = ''
 send(port, 'R %d %d' % (start, bytecount))
 response = filter(None, expect(port, True).group().split('\r\n'))
 debug('response: %s' % response)
 check_equal('0', response.pop(0), 'Error code from R command')
 dumped += uudecode(response)
 while True:
  send(port, 'OK')
  response = filter(None, expect(port, True).group().split('\r\n'))
  debug('response: %s' % response)
  if not response:
   return xxd(dumped, address = start)
  else:
   dumped += uudecode(response)
def xxd(data, address = 0, chunksize = 16, wordsize = 2):
 'dump data in xxd format'
 address_format = '%07x:' if address + len(data) < 0x10000000 else '%08x:'
 padding = [' ' * wordsize * 2] * (chunksize / wordsize)
 chunked = [data[n:n + chunksize] for n in range(0, len(data), chunksize)]
 for chunk in chunked:
  print address_format % address,
  words = [chunk[n:n + wordsize].encode('hex')
   for n in range(0, chunksize, wordsize)]
  for word in (words + padding)[:chunksize / wordsize]:
   print (word + padding[0])[:len(padding[0])],
  print ' ' + re.compile('[^ -~]').sub('.', chunk)
  address += chunksize
def init():
 port = serial.Serial(PORTS[0], baudrate = 19200, timeout = TIMEOUT)
 if TOGGLE_LINES:
  port.setDTR(1)  # DTR high forces reset
  port.setRTS(1)  # RTS high forces ISP mode (pin 14)
  time.sleep(PAUSE)
  port.setDTR(0)  # drop reset line first, holding P0.14 high
  time.sleep(PAUSE)
  port.setRTS(0)
 else:
  port.setRTS(0)
  port.setDTR(0)
 time.sleep(PAUSE)  # give SBC a chance to initialize
 return port
def safeint(number):
 if number.startswith(('0X', '0x')):
  return int(number, 16)
 else:
  return int(number)
def comm():
 port = init()
 sync(port)
 print >>sys.stderr, 'Communications established. Enter commands:'
 while True:
  try:
   command = raw_input('> ').rstrip()
   if command == 'QUIT':
    raise EOFError, 'User exited'
   send(port, command)
   print expect(port, True).group()
  except EOFError:
   print >>sys.stderr, '\r\n'
   break
 port.close()
def sync(port):
 expect(port, '', eol = None)
 send(port, '?', eol = None)
 expect(port, 'Synchronized')
 send(port, 'Synchronized')
 expect(port, ['Synchronized', 'OK'])  # because echo is still on
 send(port, CLOCK_RATE)
 expect(port, [CLOCK_RATE, 'OK'])
 send(port, 'A 0')  # turn off echo
 expect(port, ['A 0', CMD_SUCCESS])  # last echo we should get
def uudecode(lines):
 'uudecode requires begin and end; treats \r as illegal character'
 checksum = lines.pop(-1)
 message = 'begin\n' + '\n'.join(lines) + '\n \nend\n'
 debug('decoding %s' % repr(message))
 decoded = message.decode('uu')
 check_equal(int(checksum), sum(map(ord, decoded)), 'Checksum for uudecode')
 return decoded
def check_equal(expected, got, message):
 if got != expected:
  print >>sys.stderr, '%s: got %s, expected %s' % (message, got, expected)
  sys.exit(1)
def send(port, message, eol = EOL):
 debug('Sending: %s' % message)
 port.write(message + (eol or ''))
def expect(port, what, eol = EOL):
 if type(what) == str:
  debug('Expecting: %s' % repr(what))
 elif hasattr(what, 'pattern'):
  debug('Expecting match for pattern %s' % repr(what.pattern))
 elif what is True:
  debug('Expecting a response')
  what = re.compile('(?s).*')
 else:  # assume iterable
  what = eol.join(what)
  debug('Expecting: %s' % repr(what))
 message = read(port)
 match, pattern, found = check_match(message, what, eol)
 if not match:
  print >>sys.stderr, 'Expected %s, got %s' % (repr(pattern), repr(found))
  sys.exit(1)
 else:
  return match
def check_match(text, pattern, eol):
 if type(pattern) == str and pattern + (eol or '') == text:
  return True, pattern, text
 elif hasattr(pattern, 'pattern'):
  match = pattern.match(text)
  return match, pattern.pattern, text
 else:
  return False, pattern, text
def read(port, chunksize = 64):
 text = ''
 while True:
  partial = port.read(chunksize)  # must have timeout or will block forever
  if len(partial):
   text += partial
  else:
   return text
def debug(message):
 if os.getenv('DEBUGGING'):
  print >>sys.stderr, message
if __name__ == '__main__':
 command = os.path.splitext(os.path.split(sys.argv[0])[1])[0]
 print >>sys.stderr, eval(command)(*sys.argv[1:]) or ''