EEPROM Jumper question for M68EVB912B32

Started by mgrace_canlas October 7, 2003
Hello, me again.

I have a question regarding the M68EVB912B32 evaluation board.

In the EVB user's manual, it stated in Jump-EEPROM Mode, "..(W3-1
and W4-0), the EVB begins operation out of reset by executing the
user program in byte-erasable EEPROM starting at address $00D0..
(p.35)" And the EVB manual also said that "Control can be returned
to D-Bug 12 in two ways:..(p. 36)"

When I jumpered the wires to Jump-EEPROM Mode, I can still access D-
Bug features and when I reset, my test program did not run, which is
the complete opposite of what was stated in the manual..

Just wondering what happened... Is my EVB defective? Also, I tested
the same program using RAM and in EVB mode and the test program
ran...What's wrong with my Jump-EEPROM Mode?

MaryGrace Canlas




MaryGrace,

Most likely you forgot to initialize the stack pointer in your code (LDS #$0C00). The reason your code ran OK from RAM is because D-Bug12 initializes the user stack to $0C00 for you. If your code is initializing the stack pointer, it could be that your code is not disabling the COP watchdog timer (it's enabled by default on the HC12 family).

Regards,

Gordon

mgrace_canlas wrote:

>Hello, me again.
>
>I have a question regarding the M68EVB912B32 evaluation board.
>
>In the EVB user's manual, it stated in Jump-EEPROM Mode, "..(W3-1
>and W4-0), the EVB begins operation out of reset by executing the
>user program in byte-erasable EEPROM starting at address $00D0..
>(p.35)" And the EVB manual also said that "Control can be returned
>to D-Bug 12 in two ways:..(p. 36)"
>
>When I jumpered the wires to Jump-EEPROM Mode, I can still access D-
>Bug features and when I reset, my test program did not run, which is
>the complete opposite of what was stated in the manual..
>
>Just wondering what happened... Is my EVB defective? Also, I tested
>the same program using RAM and in EVB mode and the test program
>ran...What's wrong with my Jump-EEPROM Mode?
>
>MaryGrace Canlas >-------------------- >
>">http://docs.yahoo.com/info/terms/ >

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