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--- In m68HC11@y..., "Redd, Emmett R" <err557f@s...> wrote: > John, > > AFAIK, only the 68SEC711 variants are the secure chips. I don't know > how the security is implemented in hardware exactly, but I could > probably dig up the bootloader code. Security is implemented in the > bootloader and I believe the hardware forces only the single chip modes > (i.e. single chip and bootstrap Thanks Emmett for your reply. (I know it's a little late- Sorry ;-) It is not very clear from the docs. I have downloaded the latest "Pink book" and it seems to show that the normal HC711 can be protected. It simply erases the EEPROM, which is ok with me. The 'S' version seems to have additional protection where the chip becomes unusable. It refers to the (wrongly numbered) application note. Still don't understand how issuing the command MS 103f 05 CLEARS the NOSEC bit (bit 3)when it is set in $05 (%00001001). Anyone from Motorola can shed any light on this?

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