MCF52258 Not running without debugger attached

[RxScram]

Hi Everybody,

I've searched through the forums and found similar problems, but I didn't think any of the other problems were relevant.

My problem is this:  I have programmed the flash in my 52258, and if I run it with the BDM attached, it works fine.  However, if I try running it without the BDM, it does not run.  The interesting thing is that I do not do anything with the BDM... I just have it plugged in, without even having codewarrior running, and then I turn on the power and it runs fine.  If I turn off the power, unplug the BDM, and turn the power back on then nothing happens.

I think this could be a hardware design problem on my part, but I am not sure what it could be.  Any suggestions?  My BDM pinout is as suggested by the MCF52259RM document, and is basically identical to the eval board.  Since the BDM works great, I don't think that the error is in that portion.

Thank you.

[scifi · Accepted solution]

This problem should be easy to solve.

Assuming signals from the debugger are static, attach the debugger and write down the voltage levels it supplies to the MCU. Then detach it and do the same. You should now see what changed.

I have a MCF52259-based design running. No surprises, works like a charm.

[RxScram]

Thanks, I should have done that on my own first.  I needed to add a pull-up on /bkpt, it was as simple as that.

[trusc]

I had the same problem on a board using the MCF52255. Problem solved after reading your posts.

Thanks - I'm pretty pleased about having found a solution to this problem! :smileyhappy: