topic Re: USB HCS08/HCS12 MULTILINK how to protect flash from reading in 8-bit Microcontrollers

USB HCS08/HCS12 MULTILINK how to protect flash from reading

Alex_RUS — Tue, 14 Nov 2006 15:11:14 GMT

"— MC13213/214 — a high block of 59348 bytes (115 pages of 512 bytes each plus 1 page of 468
bytes) and a low block of 1920 bytes. The high block can be protected and the low block left
unprotected for use as non-volatile parameters."

I need to protect high block () and live low block unprotected for volatile variables.

Is it possible to protect my software using this BDM. How?

Re: USB HCS08/HCS12 MULTILINK how to protect flash from reading

Alban — Tue, 14 Nov 2006 20:50:00 GMT

Hi Alex,

S08 and S12 have registers to define the area to be locked against re-write/erase.

But you can still read it. This is called Flash Block Protection.

To allow people not to be able to read from BDM, you have to SECURE the device.

In this case all the memory is available to your application.

When the BDM is activated, the memory protected is removed from the memory map and therefore is inaccessible by BDM or the Software: it means you cannot run something in RAM to dump the content of the Flash.

These are two separated mechanisms.

Cheers,

Alban.

Re: USB HCS08/HCS12 MULTILINK how to protect flash from reading

Alex_RUS — Fri, 17 Nov 2006 05:56:27 GMT

I mean SECURE mechanism of course.

Is it possible to apply security to flash of mc13213 using P&E UML-12?

Re: USB HCS08/HCS12 MULTILINK how to protect flash from reading

peg — Fri, 17 Nov 2006 16:49:14 GMT

Hi Alex,

Turning on security is just a matter of programming two bits in a flash register.

You can arrange for this to be already done in the file you programme into the MPU or just programme this byte afterwards. It is not perculiar to a particular BDM adapter.

Bits 0 and 1 of NVOPT in a GB/GT

Regards

David

Message Edited by peg on 2006-11-1706:54 PM