MC9S08SH8 connection problem using BDM

[OscarRodea]

Hi everybody,

I want to program & debug a MC9S08SH8, but I cannot do that.

It shows the "Power Cycle Dialog" which says "The target MCU is not responding. Please turn MCU power off (under 0.1v(, turn MCU power on..."

I connected it as the diagram on its datasheet.

I have reset the MCU.

I have tried with two ICs.

What could I do? Do you have any idea?

Regards,

Oscar Rodea

[weapon]

Hi Oscar,

If the chip is blank, there will be one situation require repower the MCU, as blank MCUs will generate cyclic reset which will prevent MCU entering into BDM mode.

In that case, Debugger will use POR signal to enter into BDM mode. Once MCU is programed, such situation will be disappeared.

Have you try to repower MCU when the prompt Dialog is popup ?

B.R

Weiping

[Lundin]

The BDM should pull the reset line low and prevent the "cyclic reset" (which I assume is the watchdog?). I've never had the problem your describe with any blank chip. But then I've only used BDM adapters from PE micro and Softec. Perhaps there exists home-brewed BDMs that are crap and cannot do this...?

[weapon]

Hi Daniel,

I also mentioned P&E multilink. as my understanding, BDM won't pull down reset pin during the process of entering into BDM mode. reset will cause the communicaiton fail. the cyclic reset is caused by illegal opcode usually.  please check the application note below for detail:

http://cache.freescale.com/files/microcontrollers/doc/app_note/AN3762.pdf?fasp=1&WT_TYPE=Application...

B.R

Weiping

[Lundin]

There are many possible reasons. The first basic steps to trouble-shoot issues like these would be:

- Ensure that you actually didn't connect the BDM connector backwards.

- Measure the voltage levels to the MCU. Ensure that it has a proper supply. Ensure that you also have this supply voltage on the BDM connector.

- Measure the CPU clock. Is alive and working?

- Ensure that you have the correct components mounted on the reset and BKGD lines. The reset should have a 100nF decoupling cap and an optional pull-up resistor. The BKGD line should not have a decoupling cap.

- Measure the reset line. Is it steadily high when the device is idle? What happens when you try to program, can the BDM successfully pull reset low? Does the edges of the digital signal look ok?

- Similarly, measure the BKGD line. There should be digital data rushing through there when you try to program.

When doing all of the above, always measure on the actual MCU pin, to ensure that every component is soldered properly.