According to the Microchip documentation (Microcontroller Data Book 1996/7),
even in the protected mode the low nibble of the configuration word on 16C54
reads unscarmbled. The code protect feature scrambles the output in the
following way: bits 4 to 11 are all zeros and the low nibble equals to XOR
of all three nibbles. Since the bits 4-11 of the config word are all ones,
they XOR to all zeros and do not change the low nibble.

Someone called me recently with a similar problem, he had some 30 OTP PICs
programmed with a buggy code. He is trying to erase these chips with a
therapy X-ray machine. The diagnostic one turned out to be too weak. He
promised to call me what the results are, so do not trash them yet.

Even if everything fails, you may still find an artist and have your 54's
arranged in some interesting sculpture ;-).

Josef Hanzal
euroclass@pha.pvtnet.cz