8-bit MicrocontrollersのトピックRe: Beginners question QG4/QG8

Beginners question QG4/QG8

Ralph — Fri, 23 Jun 2006 22:32:46 GMT

Hi!
I am new to HCS08QG8 so the question may be dumb. Some years ago I played around already with 68332 and BD32 (DOS-Debugger), now I want to use the mentioned device and Code Warrior 5.0.
I have started with the DEMO9S08QG8 and wrote some Code. Since our distributor had the QG4 on stock and the lower memory will be enough for my application I have ordered the QG4. Since I am a little curious I didn't change the device in CW5.0 and awaited an error because the flash of the QG4 starts at $F000 instead of $E000 of the QG8. But there seems to be no problem. To verify that I've written code with two ascii test strings with the org command to $EA00 and another to $F000. Both are there in the memory window!
Setting the device to QG4 in CW5.0 results for sure in "00" from $E000 to $EFFF.
Has somebody got an idea why this happens?
Best Regards
Ralph

P.S.: "P&E Multilink/Cyclone Pro" is selected as debugger.

Re: Beginners question QG4/QG8

tonyp — Sat, 24 Jun 2006 03:20:57 GMT

Have you tried with another chip (preferrably from a different batch)? Does it still happen?

If only some chips do this, one possibility is that during production (of would-be QG8) some Flash fails the tests while the rest (within the QG4 range) passes. Freescale "baptises" the chip QG4, and you end up with a little "bonus" that you probably shouldn't trust (the extra memory, that is) for production but can be used for playing. They used to do that with HC11s. You ordered a ROM-less part to find either Buffalo or some other firmware in the on-chip ROM. [This actually saved me once in a production unit, when (for reasons too complicated to mention here) the part switched from expanded to single-chip mode and auto-executed the built-in Buffalo. I used Buffalo to set it back to using expanded mode.]

Then again, it could be a totally unrelated issue having to do with CW's debugging facilities of which I know nothing about as I don't use it (e.g., a "ghost" image that isn't really in the chip, only on the debugger's window).

Message Edited by tonyp on 2006-06-23 11:24 PM

Re: Beginners question QG4/QG8

Pingu — Thu, 29 Jun 2006 19:43:10 GMT

The first description from tonyp is the correct one in this case.

Re: Beginners question QG4/QG8

Ralph — Thu, 06 Jul 2006 20:01:38 GMT

Hi!
Many thanks to tonyp and Pingu! Meanwhile I was very busy with debugging the hardware and some software bugs in my firmware, that's the reason why I am answering very late.
I have done some tests and the memory seems to be there really. As Pingu wrote, the QG4 seem to be QG8 with a failure in flash (or maybe ram) area that is only used by the QG8.
Many thanks again for your replies!
Have a nice day!
Best regards
Ralph