topic EEPROM on 9s12x512 in CodeWarrior for MCU

EEPROM on 9s12x512

Keep_Smiling_2 — Tue, 05 Dec 2006 02:26:59 GMT

I can read and write 2045 locations in the EEPROM addressing space starting at

EEPROMStart and going 2045 locations. When I try to access the rest of the 4k

the processor hangs and resets itself? Any clues?

Thank you.

Re: EEPROM on 9s12x512

J2MEJediMaster — Tue, 05 Dec 2006 23:13:22 GMT

I'm looking at the MC9S12XDP512 family data sheet (MC9S12XDP512V2.pdf) and it appears that the most this part could have is 4K of EEPROM. I don't know what size you access your "location" as, but if it's a word or larger you might be running off the end of EEPROM memory and triggering an illegal address reset exception.

---Tom

Re: EEPROM on 9s12x512

Keep_Smiling_2 — Wed, 06 Dec 2006 02:11:35 GMT

Tom,

Yes, It is suppoased to be 4K, but as soon as I try to read or write the 2046th location the reset takes me into the weeds..... I know I read that there is about 4 locations of unusable space for overhead. I'm using the Processor expert to access each byte of EEPROM: EEPROMStart + OFFSET is valid until the 2046th location is addressed. Any clues now?

Terry

Re: EEPROM on 9s12x512

Alban — Wed, 06 Dec 2006 21:11:12 GMT

Hi Terry,

I'm not sure you'll keep smiling, but I'll try anyway.

Is it data store/read you do from these locations, or code execution ?

Code Execution has a prefetch pipeline as documented in the CPU reference manual. If you fetch outside implemented memory, you get a Illegal Address Reset....

Cheers,

Alban.