topic Unable to go into background mode in 8-bit Microcontrollers

Unable to go into background mode

gutighus — Tue, 03 Jun 2008 04:26:01 GMT

Hello,

I am a collage student just starting to work with Freescale. Currently I´m programming in assembler in a HC08AP16 uC. I´m trying to implement a program in the uC, but for some reason is not working. It seems as if it automatically resets itself. So I decided to simulate it directly from the uC. I start the process by doing single steps, but then like at the 10th instruction, the following error shows: "Unable to go into background mode" It says that the Reset was caused by External reset pin. But that is imposible, because the reset pin has nothing connected to it.

And no matter what I do to the program, I keep getting the same error. And it always happens to be at the beginning of the program.

I really cannot find my way around this problem.............any suggestions?

Thanks,

Daniel

Re: Unable to go into background mode

Ake — Tue, 03 Jun 2008 16:52:53 GMT

Hi,

I read your message but could not understand what went wrong.

Here is another program called AP16 IO that I think you should try first.

Once you get it running, you can start to modify it.

It is compressed with WinZip, .

So decompress it and try it first.

Regards,

Ake

Re: Unable to go into background mode

gutighus — Fri, 06 Jun 2008 01:00:02 GMT

Hello,

Thanks for the program, although it was pretty basic, but at the same time useful. Becuase I program in asm and this was good for an intro to c. But I was finally able to fix the problem. The problem was that the AP16 only has 6 pins for the port C. And at the moment I was configuring the DDRC registry, I was configuring the 8 bits as outputs. So I had to fix it to only 6 bits. This is a problem that the compiler doesn't see or the Full time simulator. So just as a heads up on my previous post.

Thanks,

Daniel

Re: Unable to go into background mode

bigmac — Fri, 06 Jun 2008 09:18:25 GMT

Hello Daniel,

Even though the 42-pin version of the device does not have PTC0 and PTC1 bonded out, these bits still exist internally. It is perfectly reasonable to set these as outputs, (and a very good idea so as to prevent a floating input situation). I can't see that this would be the cause of your previous problem.

When you experienced the problem, were you using the actual hardware for the test, or were you simulating the hardware in full chip simulation mode?

I would also suggest that, while you are experimenting, that you disable COP timer operation. Unless properly handled, this can cause a reset.

Regards,

Mac