topic Re: Can't start Micro without CW Real Time Debugger connected in OSBDM and TBDML

Can't start Micro without CW Real Time Debugger connected

sauliuz — Wed, 22 Nov 2006 19:20:30 GMT

Hi,

I am writing program with C for MC9S12C32. I am using Turbo BDM Light interface (by Daniel Malik). I download code to the device with Code Warrior Real Time debugger (RTD). The problem is that I can not start the device when disconnected from RTD. When it is connected the code works (SCI, timers...). When I disconnect RTD (I mean the programming wires to RESET and BKGD pins) and reset the power - it hangs. I checked:
1. I get low pulse of ~8.4us on the reset pin after reset.
2. When device starts it should turn on the LED on a pin. And keep it on. After reset the LED blinks once. I get a pulse for about 16,4ms. (I use 15 MHz quartz). - It seem that it start and then goes down.
3. I tried to start a new project in Code Warrior with pure assembler, and wrote couple of lines to toggle the pins. After downloading the code to device and disconnecting the RTD it worked!!! I make a conclusion that when compiling C, CW also adds extra code for real time device debugging, which then halts the device when RTD not connected.

Does anybody know were is the problem?
Any help will be very valuable - confused....

Re: Can't start Micro without CW Real Time Debugger connected

CompilerGuru — Thu, 23 Nov 2006 01:08:10 GMT

the "usual" things for this type of failures:
- COP
- special modes (and different rules for write once registers)
- (reset) vector

Daniel

Re: Can't start Micro without CW Real Time Debugger connected

sauliuz — Thu, 23 Nov 2006 19:51:54 GMT

Yes that was COP problem. Thanks.
The C code for __RESET_WATCHDOG(); is define in mc9s12c32.h as:
#define __RESET_WATCHDOG() {asm staa COPCTL;} /* Just write a byte to feed the dog */
which is not right as I see from data sheet.
So I changed it to my code (instead of __RESET_WATCHDOG()):
initialize watchdog in the main (the longest period, normal mode):
COPCTL = 0x07;
and restart watchdog code in the main forever loop:
ARMCOP = 0x0055;
ARMCOP = 0x00AA;

But now I face another problem. I made a changeable delay to test the watchdog. It seems that it works at the right time. But after reset happens the device hangs - it looks like it does not start as it does after power off reset. ??? Does anybody knows why?

Re: Can't start Micro without CW Real Time Debugger connected

Lundin — Thu, 23 Nov 2006 21:54:41 GMT

If you have the debugger up and running it may place the CPU in stop mode and then the watchdog will freeze as well.
Do you get the same behaviour without any BDM connected to the device?

Also check that the COP reset vector (FFFA-FFFB) is pointing at the default reset vector (FFFE-FFFF).