hexgen.py

#!/usr/bin/env python

# Here's a useful skeleton for generating (in this case) an intel hex file
# for filling size bytes with 0xff; it can be easily modified to convert
# bytes from stdin.

size = 0x200
offset = 0
blocksize = 16

while size > 0:
    codes = []
    linesize = min(blocksize,size)
    codes.append(linesize)
    codes.append(offset>>8)
    codes.append(offset&0xff)
    codes.append(0) # data code
    codes.extend([0xff] * linesize)
    # calculate checksum
    checksum=(0x100-(sum(codes)&0xff))&0xff
    codes.append(checksum)
    print reduce(lambda s,v:s+'{0:02X}'.format(v), codes, ":")
    offset += linesize
    size -= linesize