[ARM] TIMER PROBLEM in LPC2129

[v.s.n.kumar]

Hi,
please can anybody help me to solve the below problem. i have been facing this problem since 3days. i.e., cclk=12mhz, pclk=3mhz. i have created a time delay of 2 seconds and used as delay function to blink and led. when i debugged this code, after 2seconds i.e., the timer counter value doesn't reset even though i used the instruction T0TCR=1<<1. please anybody can solve my problem...........

#include<LPC21xx.h>
#define LED 1<<1
void delay(void);
void main()
{
 IODIR0=LED;
 T0PR=2999999;
 while(1)
 {
   IOSET0=LED;
   delay();
   IOCLR0=LED;
   delay();
 }
}
void delay(void)
{ 
 T0TCR=(1<<1);
 T0TCR=(1<<0);
 while(!(T0TC==2));
 T0TCR=(0<<0);
}

 

[alexan_e]

download the lpc2300 code bundle http://www.lpcware.com/content/nxpf...pc23xxlpc24xx-peripherals-using-keils-μvision in the folder common/src/timer.c you will find the following function

---

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
/*****************************************************************************
** Function name:       delayMs
**
** Descriptions:        Start the timer delay in milo seconds
**                      until elapsed
**
** parameters:          timer number, Delay value in milo second             
**                      
** Returned value:      None
** 
*****************************************************************************/
void delayMs(BYTE timer_num, DWORD delayInMs)
{
  if ( timer_num == 0 )
  {
    /*
    * setup timer #0 for delay
    */
    T0TCR = 0x02;       /* reset timer */
    T0PR  = 0x00;       /* set prescaler to zero */
    T0MR0 = delayInMs * (Fpclk / 1000-1);
    T0IR  = 0xff;       /* reset all interrrupts */
    T0MCR = 0x04;       /* stop timer on match */
    T0TCR = 0x01;       /* start timer */
  
    /* wait until delay time has elapsed */
    while (T0TCR & 0x01);
  }
  else if ( timer_num == 1 )
  {
    /*
    * setup timer #1 for delay
    */
    T1TCR = 0x02;       /* reset timer */
    T1PR  = 0x00;       /* set prescaler to zero */
    T1MR0 = delayInMs * (Fpclk / 1000-1);
    T1IR  = 0xff;       /* reset all interrrupts */
    T1MCR = 0x04;       /* stop timer on match */
    T1TCR = 0x01;       /* start timer */
  
    /* wait until delay time has elapsed */
    while (T1TCR & 0x01);
  }
  return;
}

---

You just need to define the Fpclk which represents your clock frequency and maybe change the register names of the timer in case they are different (usually not the case)