EEPROM erase/ write problem

[rdkarthik]

Hello All,

I am using a 9s12dg128 controller and P&E ICD. The EEPROM erase and write routines work fine as long as the BDM is connected and debugger is running, but fails to do so otherwise.

I use a 16Mz oscillator. I have also tried initializing EEPROM related registers the way codewarriror erase command does. There are no protection or access errors. EEPROM is readable. Disabled COP. Disabled PLL. Tried different values of ECLKDIV within range.  But nothing seems to work.I was not able to gather anything specific to this problem from the datasheets or errata either.

Any help would be appreciated.

Thanks in advance.

Karthik.

[Lundin]

Maybe you are writing to ECLKDIV more than once? In that case you would get the behaviour you describe since that register is "write once" in normal single chip mode, ie when the BDM isn't connected to put the mcu in special single chip mode.

And then you would get the wrong ECLKDIV and the eeprom won't work. I once made that mistake myself:

/* bad */
ECLKDIV = calculated_value;
ECLKDIV |= PRDIV8;

/* good */
ECLKDIV = calculated_value | PRDIV8;