Jean Delvare wrote: .. > >># dump/i2cdump 0 0x19 b >> 0 1 2 3 4 5 6 7 8 9 a b c d e f >>00: 24 26 00 00 00 50 50 64 64 64 64 64 64 64 64 64 >>10: 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 >>20: 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 >>30: 21 22 22 22 22 00 00 00 5a 5a 6e 6e 6e 6e 6e 6e >>40: 6e 6e 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>50: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>60: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>70: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>80: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>90: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>a0: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>b0: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>c0: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>d0: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>e0: 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f >>f0: 00 85 18 35 26 26 26 00 38 25 24 24 24 24 01 03 > > > That's very interesting. See how the limits appear not only in one, but > many registers. I had never seen this behavior. Could be used for > detection purpose (although we already have a reliable detection > mechanism now, thanks to you). what you're seeing is a relatively common behavior where, when you read an invalid location, it returns the value from the last valid read. So it depends on the order you read things. I would be wary of using this for detection purposes.
