Jim Pantera

security and emulation writes to flash

Discussion created by Jim Pantera on Nov 6, 2006
Latest reply on Nov 12, 2006 by David Payne
reference the mc9s08rd32dwe processor

while using a commerical programmer production has security locked the processor by setting the flash register NVOPT/SEC01:smileyfrustrated:EC00 = 1:0 later at power up NVOPT gets copied to FOPT and the processor is locked. for a situation that emulation will need to write to a random flash page the processor is now locked and the write will not happen.

i need to use the backdoor, i dont know which page emulation will write to and assume all pages will be protected.

can you guys verify my fix would entail:
-i need to add code to use the NVBACKKEY register(s) the security backdoor.
-i know i need to write to NVBACKKEY[0] through NVBACKKEY[7] in order from emulation but DO I NEED TO DO THIS FROM RAM NOT FLASH!!
-can i do the writes using Clanguage like the code:
NVBACKKEY[0] = Secret[0];
NVBACKKEY[1] = Secret[1];
NVBACKKEY[2] = Secret[2];
NVBACKKEY[3] = Secret[3];
NVBACKKEY[4] = Secret[4];
NVBACKKEY[5] = Secret[5];
NVBACKKEY[6] = Secret[6];
NVBACKKEY[7] = Secret[7];
-is there ram based assy code already existing that i could use??