Author Topic: Security bits in unused blocks?  (Read 3080 times)


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Security bits in unused blocks?
« on: November 02, 2006, 07:43:41 am »
I've got code that fits in Blocks 0 to 2 of a 922. Somehow (don't know how), the security bits for Block 3 got set. When I reprogram the software, with the security bits cleared for all blocks, the Block 3 bits are still programmed.

Does this mean that FM programs only the security bits for the blocks that have code in them? Or am I missing something?



Andy Ayre

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Re: Security bits in unused blocks?
« Reply #1 on: November 02, 2006, 07:57:18 am »
FM programs exactly the security bits you tell it to and nothing more. So if the box for the security bit is checked in the main window then it will be programmed. Otherwise it will be left in it's current state.

What happens if you do the following:

ISP -> Read Security Bits
  -> check that the block 3 bits are set
ISP -> Erase
  -> erase all Flash
ISP -> Read Security Bits
  -> which bits are still set?

Main window, section 4
  -> are any security bit checkboxes set?

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