Hi

Can anyone help me. I am using a button press to cause the wdog to 
reset my application.
I use

      WDTCTL = WDT_ADLY_1000;
      IE1 |= WDTIE;
      while(1);
I dont relaod the wdog so the device resets.

Then at initialisation I use

  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

  // Xtal related activity
  // Set the ACLK to use the 3.6864MHz Xtal
  BCSCTL1 |= XTS;                       // ACLK = LFXT1 = HF XTAL
  // Ensure that the XTAL STARTS UP 
  do 
  {
    IFG1 &= ~OFIFG;                       // Clear OSCFault flag
    for (i = 0xFFF; i > 0; i--);           // Time for flag to set
  }
  while ((IFG1 & OFIFG) != 0);          // OSCFault flag still 
set?                
  // Set the Master Clock to the Xtal
  BCSCTL2 |= SELM1+SELM0;               // MCLK = LFXT1 (safe)


I used to have 0xff in the 'for' loop but lengthened it to try 
improving the reset.

I have a cmac A169E 3.6864 Mhz xtal and 3.9pF caps to 0v from the xtal
(I used to have 22 pF previously - same problem).
The data sheets reccomends nominally 2pF.

My problem is that when I reset the device it doesn't always return 
to normal operation.
It either sits waiting for the oscillator to initialise or it jumps 
off into some unused part of memory.

Has anyone come across this and if so do you have any suggestions to 
overcome it.

Cheers

Peter

Two observations:
1) you can cause an immediate RESET via the WD
by simply writing 0 to it (invalid WDTPW)

WDTCL = 0;
while (1);

2) ensure that ((IFG1 & OFIFG) == 0) constantly for
at least 255 accesses.

  for (IFG1 &= ~OFIFG, delay = 255; delay; )
    {
    if (IFG1 & OFIFG)                   // check OSC fault flag
      {
      // it's set
      IFG1 &= ~OFIFG;                   // clear OSC fault flag
      delay = 255;                      // reset delay count
      }
    else
      --delay;                          // clear, decrement delay
    }

Regards
-Bill Knight
R O SoftWare





On Fri, 27 Feb 2004 15:33:52 -0000, pjascol wrote:

Hi

Can anyone help me. I am using a button press to cause the wdog to 
reset my application.
I use

      WDTCTL = WDT_ADLY_1000;
      IE1 |= WDTIE;
      while(1);
I dont relaod the wdog so the device resets.

Then at initialisation I use

  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

  // Xtal related activity
  // Set the ACLK to use the 3.6864MHz Xtal
  BCSCTL1 |= XTS;                       // ACLK = LFXT1 = HF XTAL
  // Ensure that the XTAL STARTS UP 
  do 
  {
    IFG1 &= ~OFIFG;                       // Clear OSCFault flag
    for (i = 0xFFF; i > 0; i--);           // Time for flag to set
  }
  while ((IFG1 & OFIFG) != 0);          // OSCFault flag still 
set?                
  // Set the Master Clock to the Xtal
  BCSCTL2 |= SELM1+SELM0;               // MCLK = LFXT1 (safe)


I used to have 0xff in the 'for' loop but lengthened it to try 
improving the reset.

I have a cmac A169E 3.6864 Mhz xtal and 3.9pF caps to 0v from the xtal
(I used to have 22 pF previously - same problem).
The data sheets reccomends nominally 2pF.

My problem is that when I reset the device it doesn't always return 
to normal operation.
It either sits waiting for the oscillator to initialise or it jumps 
off into some unused part of memory.

Has anyone come across this and if so do you have any suggestions to 
overcome it.

Cheers

Peter





.


Yahoo! Groups Links

Thanks Bill

I put your idea number 2 into action first.  I still had the problem.

Then I included suggestion 2 and it appears to have sorted it.
BUT, what is it about 
       WDTCTL = WDT_ADLY_1000;
that upset it so much that my application would not start up again.

Any suggestions anyone, I'd love to know

Once again, thanks Bill

Cheers 
Peter



--- In msp430@msp4..., "Bill Knight" <BillK@r...> wrote:
> Two observations:
> 1) you can cause an immediate RESET via the WD
> by simply writing 0 to it (invalid WDTPW)
> 
> WDTCL = 0;
> while (1);
> 
> 2) ensure that ((IFG1 & OFIFG) == 0) constantly for
> at least 255 accesses.
> 
>   for (IFG1 &= ~OFIFG, delay = 255; delay; )
>     {
>     if (IFG1 & OFIFG)                   // check OSC fault flag
>       {
>       // it's set
>       IFG1 &= ~OFIFG;                   // clear OSC fault flag
>       delay = 255;                      // reset delay count
>       }
>     else
>       --delay;                          // clear, decrement delay
>     }
> 
> Regards
> -Bill Knight
> R O SoftWare
> 
> 
> 
> 
> 
> On Fri, 27 Feb 2004 15:33:52 -0000, pjascol wrote:
> 
> Hi
> 
> Can anyone help me. I am using a button press to cause the wdog to 
> reset my application.
> I use
> 
>       WDTCTL = WDT_ADLY_1000;
>       IE1 |= WDTIE;
>       while(1);
> I dont relaod the wdog so the device resets.
> 
> Then at initialisation I use
> 
>   WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
> 
>   // Xtal related activity
>   // Set the ACLK to use the 3.6864MHz Xtal
>   BCSCTL1 |= XTS;                       // ACLK = LFXT1 = HF XTAL
>   // Ensure that the XTAL STARTS UP 
>   do 
>   {
>     IFG1 &= ~OFIFG;                       // Clear OSCFault flag
>     for (i = 0xFFF; i > 0; i--);           // Time for flag to set
>   }
>   while ((IFG1 & OFIFG) != 0);          // OSCFault flag still 
> set?                
>   // Set the Master Clock to the Xtal
>   BCSCTL2 |= SELM1+SELM0;               // MCLK = LFXT1 (safe)
> 
> 
> I used to have 0xff in the 'for' loop but lengthened it to try 
> improving the reset.
> 
> I have a cmac A169E 3.6864 Mhz xtal and 3.9pF caps to 0v from the 
xtal
> (I used to have 22 pF previously - same problem).
> The data sheets reccomends nominally 2pF.
> 
> My problem is that when I reset the device it doesn't always return 
> to normal operation.
> It either sits waiting for the oscillator to initialise or it jumps 
> off into some unused part of memory.
> 
> Has anyone come across this and if so do you have any suggestions 
to 
> overcome it.
> 
> Cheers
> 
> Peter
> 
> 
> 
> 
> 
> .
> 
> 
> Yahoo! Groups Links