Hi,

No, no, that doesn't happen. We are talking about binary data, zeros and ones. We compare the dumps bit by bit, there is no tolerance possible. If two dumps have for example one different bit, it can be: because the program is really different, due for example to a bug fix; because the data was stored in an EPROM and due to failure or aging that byte has been "corrupted"; etc.

But in the Hitachi microprocessors we are talking about, the ROM is stored in MaskROM and doesn't suffer "corruption" due to aging as it happens with EPROMs. So no, there is no tolerance... if 1 million of H8 microcontrollers are manufactured with a given binary code, and the programming of that ROM is verified in the manufacturing process, they will all contain the same data in the ROM unless there is a later damage...

Best,
Gerardo