Lpc2000

Refering to my earlier response, the

>       VICVectAddr = 0;
should be the last thing the high-level IRQ handler should do (the routine
whose address is in the exception vector IRQ slot).

  -----Original Message-----
  From: peterburdine [mailto:lordofdawn@...]
  Sent: Wednesday, March 30, 2005 12:14 PM
  To: lpc2000@yahoogroups.com
  Subject: [lpc2000] Re: Strange timer problem



  I figured it out.  It didn't work as and irq, so I switched it to fiq
  and added VICIntSelect = 1<<4; and it seems to work just fine now.
  Although I wonder why it didn't work as an irq.  And yes I know that
  when the msg was first posted I had __fiq on the ISR, that was my
  halfway between code, I had __irq on them originally.

  --Peter

  --- In lpc2000@yahoogroups.com, "peterburdine" <lordofdawn@h...> wrote:
  >
  > I'm using the Keil's compiler and I'm trying to setup a system clock
  > that increments every 5ms.  I am doing this by having a unsigned long
  > int that gets incremented on the timer interrupt.  The timer also
  > resets when the interrupt occurs.  The problem is this seems to
  > somehow corrupt a few registers every once in a while and will
  > generally end up in a data abort.  I believe the timer must be the
  > cause because if I remove it, I no longer have these problems.
  >
  > I'd appreciate any suggestions.
  >
  > The applicable code is listed here:
  >
  > unsigned long int getTickCounter (void);
  > void T0_ISR (void) __arm __fiq;
  > unsigned long int tickCount = 0;
  >
  >
  >
  >       T0MR0 = PCLK/200; // Every 50ms
  >       T0IR = 0xF;      // Clear Interrupts on MR0
  >       T0MCR = 0x03;  // Reset and Interrupt on MR0
  >       VICIntEnable = 1 << 4;
  >       VICVectAddr3 = (unsigned long)T0_ISR;
  >       VICVectCntl3 = 0x20 | 4;
  >       T0TCR = 0x2;      // Reset the timer
  >       T0TCR = 0x1;      // Start the timer
  >
  >
  > void T0_ISR(void) __arm __fiq {
  >       tickCount++;
  >
  >       // Clear Interrupts
  >       VICVectAddr = 0;
  >       T0IR = 0x1;
  > }
  >
  >
  > This is a very useful function!
  > void DAbt_Handler(void) __arm __irq {
  >       Uint32 i;
  >       // Grab the return address (location where mem access failed)
  >       __asm      {STAV R14, R0, i};
  >       printf("*****Data abort occured 0x%x *****", i);
  >       // Now just spin
  >       while(1);
  > }




        Yahoo! Groups Sponsor
              ADVERTISEMENT





----------------------------------------------------------------------------
--
  Yahoo! Groups Links

    a.. To visit your group on the web, go to:
    http://groups.yahoo.com/group/lpc2000/

    b.. To unsubscribe from this group, send an email to:
    lpc2000-unsubscribe@yahoogroups.com

    c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



[Non-text portions of this message have been removed]