flash27.py

#! python2.7
import serial, sys, struct, time

if len(sys.argv) != 3:
    print 'usage: %s <port> <firmware.hex>' % sys.argv[0]
    sys.exit(1)

class PI():
    def __init__(self, com):
        self.ser = serial.Serial(com, 1000000, timeout = 1)

    def conf(self,):

        # init Programming Interface (PI)
        while True:
            try:
                self.ser.write('\x01\x00')
                x =struct.unpack('B', self.ser.read(1))[0]
                print 'x:',hex(x)
                assert(0x81 == x)
                break
            except:
                while self.ser.read(1) != '': pass

        print 'PI initiated'


    def prog(self, firmware):

        print 'Connected'

        #f = open(firmware,'r').readlines()
        f = firmware.splitlines()

        self.conf()

        # erase device
        self.ser.write('\x04\x00')
        assert(0x84 == struct.unpack('B', self.ser.read(1))[0])

        print 'Device erased'

        # write hex file
        total = 0
        buf = ''
        buf_size = 0
        for i in f[1:-1]:  # skip first and second lines
            assert(i[0] == ':')
            size = int(i[1:3],16)
            assert(size + 4 < 256)
            if buf_size == 0:
                addrh = int(i[3:5],16)
                addrl = int(i[5:7],16)
            assert(i[7:9] == '00')
            data = i[9:9 + size*2]
            assert(len(data) == size*2)

            buf += data
            buf_size += size

            if buf_size > 256 - 0x20 or i == f[-2]:
                attempts = 0
                while True:
                    try:
                        print hex(addrh), hex(addrl), buf
                        crc = addrh + addrl
                        crc += sum([struct.unpack('B', x)[0] for x in buf.decode('hex')])
                        assert(len(buf.decode('hex')) == buf_size)
                        self.ser.write([0x3, buf_size + 4 + 1, buf_size, 0, addrh, addrl, crc & 0xff])
                        self.ser.write(buf.decode('hex'))
                        ret = struct.unpack('B', self.ser.read(1))[0]
                        if ret == 0x83:
                            pass
                        else:
                            print 'error flash write returned ', hex(ret)
                            raise RuntimeError('bad crc')
                        break
                    except Exception as e:
                        attempts += 1
                        self.conf()
                        print e
                        print 'attempts:',attempts
                total += buf_size
                buf_size = 0
                buf = ''
                print 'Wrote %d bytes' % total

        # reset device
        self.ser.write('\x02\x00')
        assert(0x82 == struct.unpack('B', self.ser.read(1))[0])

        # reset device
        self.ser.write('\x02\x00')
        assert(0x82 == struct.unpack('B', self.ser.read(1))[0])

        # reset device
        self.ser.write('\x02\x00')
        assert(0x82 == struct.unpack('B', self.ser.read(1))[0])



        print 'Device reset'

print 'Once'
port=sys.argv[1]
firmware=open(sys.argv[2], 'r').read()
programmers = PI(port)

programmers.prog(firmware)