Programming Problem P&E Multilink

[DRichards]

Hi,

I am having trouble programming a new target board using an MC9S08LL8. This board is a development from a previous project and has the same connections and layout. If I use a Cyclone Pro to do the programming, it works. If I try to use a P&E Multilink connected to my PC I get a failure to connect to device although the target device does appear to be recognised. I get a number of lines in the command window of "Frequency change to ~0hz." Both the blue and yellow LEDS are lit.

If I try to programme a micro that has previously been programmed on the Cyclone Pro it is successful.

Since the previous project, my PC has changed from Windows XP to Windows 7, so I downloaded and installed the latest drivers from the P&E site (and re-booted). This did not make any difference.

Is there anything else I might have missed?

Micro MC9S08LL8.

Programmer P&E Multilink.

I am using Code Warrior IDE version 5.9.0.

[DRichards]

Having read more posts on this and the P&E forum I found mention of pull-up resistors on the BGND and RESET lines. We have never needed these before and I believed they were only necessary with a long connection to the target board. Nevertheless it was worth trying, so 10k pull-ups were added the the programming adaptor of the P&E USB Multilink. I can now program the new boards.

What the mystery is here is why the pull-ups are necessary now when they weren't needed before. The connection to the micro is extremely short and the layout as far as the programming lines go is identical to the previous product. The P&E Multilink is the same one I have always used. The biggest change is that I have a new PC running Windows 7 rather than XP, but the pull-ups are on the connection between the P&E Multilink and the target.

[DRichards]

The problem is not over. I added pull-up resistors (10k) to the taget board which then allowed me to program it by starting the debugger. Unfortunately, if I then try to run the code a reset occurs. It looks like I need the pull-ups to program the board but I can't then run it with the resistors fitted. I will try higher value resistors to see if I can find a compromise, but surely I'm missing something here?

P.S. I don't know how to remove the Assumed Answered from this topic.

[DRichards]

The reset was occurring due to an intermittant break in one of the power leads. That just leaves the question of why I need the pull-ups.