--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/micropython/hexlifyscript.py	Thu Nov 26 23:10:14 2015 +0100
@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+
+'''
+Turn a Python script into Intel HEX format to be concatenated at the
+end of the MicroPython firmware.hex.  A simple header is added to the
+script.
+
+To execute from command line: ./hexlifyscript.py <script.py>
+'''
+
+import sys
+import struct
+import binascii
+
+SCRIPT_ADDR = 0x3e000 # magic start address in flash of script
+
+def hexlify_script(script):
+    # add header, pad to multiple of 16 bytes
+    data = b'MP' + struct.pack('<H', len(script)) + script
+    data = data + bytes(16 - len(data) % 16)
+    assert len(data) <= 0x2000
+
+    # convert to .hex format
+    output = []
+    addr = SCRIPT_ADDR
+    assert(SCRIPT_ADDR >> 16 == 3) # 0x0003 is hard coded in line below
+    output.append(':020000040003F7') # extended linear address, 0x0003
+    for i in range(0, len(data), 16):
+        chunk = data[i:min(i + 16, len(data))]
+        chunk = struct.pack('>BHB', len(chunk), addr & 0xffff, 0) + chunk
+        checksum = (-(sum(chunk))) & 0xff
+        hexline = ':%s%02X' % (str(binascii.hexlify(chunk), 'utf8').upper(), checksum)
+        output.append(hexline)
+        addr += 16
+
+    return '\n'.join(output)
+
+if __name__ == '__main__':
+    # read script from a file and print out the hexlified version
+    with open(sys.argv[1], 'rb') as f:
+        print(hexlify_script(f.read()))