Summary based on mini2440 timer module

1. From the document, we can know that mini2440 has a total of 5 timers. As shown in the following figure:

Among them, the four registers of timer 0, 1, 2, and 3 have output pins, which are combined with the buzzer. Timer 4 has no output pin, so timer 4 is used exclusively for timing.

Timers 0 and 1 share an 8-bit frequency divider, and timers 2, 3, and 4 share an 8-bit frequency divider.

T = times * cycle = 1/fre(pwm) where: cycle = 1/f = 1/(50M/(prescaler+1)/(divider value).

About the configuration method of timer 4:

1. From the schematic diagram above, we can know that we need to input a PCLK first (the size is 50M, which has been set in the startup code).

Then it passes through an 8-bit divider, the value can be between (0 and 255). Then it passes through a clock divider (the value can be 2, 4, 8, 16)

So first we should configure the divider and divider value (the corresponding registers are TCFG0, TCFG1).

2. We need to configure

Setting times

3. Configuration:

First, we need to set the manual update bit and auto reload bit (TCON)

Then, we need to set up the timer interrupt. For the interrupt method, see the document of the interrupt summary.

Next, we need to set the start bit and clear the manual update bit.

In this way, we have completed setting a timer.

How to set timer 0:

1. First, we need to set the corresponding output pins (as can be seen from the schematic diagram).

2. Secondly, we need to set the divider value and divider value. (TCFG0, TCFG1).

3. Again, we need to configure the initial value and comparison value of the number of times, where the comparison value determines the reversal moment of the level.

4. Then, we need to set the manual update bit and auto reload bit (TCON)

Next, we need to configure the timer interrupt. For the interrupt method, see the relevant documentation for interrupt configuration.

Finally, we start our timer. We need to set the start bit and clear the manual update bit.

In this way, timer 0 is configured.

The timer related code is as follows:

/************************************************

  NAME    : PWM.C

  DESC   :

  Revision: 2015.8.18 ver 0.0

 ************************************************/

 #include "pwm.h"

 #include "led.h"

 #include "music.h"

 #include "uart.h"

 volatile  unsigned int div=0;

 volatile  unsigned int div10ms=0;

 volatile  unsigned int t=0;

 volatile  unsigned int t1=0;

 extern void Delay_MS( unsigned int time);

 volatile int count = 0;

 // Tone frequency table

unsigned  Syllable_freq[30]={

      262,294,330,349,392,440,494,50000000,0,0,

      523,587,659,698,784,880,988,0,0,0,

      1046,1175,1318,1397,1568,1760,1976,0,0,0

      };

void delayns(volatile int ns) //delay 200ms

{

 t=(int)ns*200;

 while(1)

 {

  if(t==0)

  {

  break;

  }

 }

}

void delayns1(volatile int ns) //delay 1s

{

 t1=(int)ns*1000;

 while(1)

 {

  if(t==0)

  {

  break;

  }

 }

}

/***********************************************

Function  name  :   timer4_irq

Description: Timer 4 interrupt service function

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/

static void __irq timer4_irq(void)

{

 rSRCPND |= BIT_TIMER4;

    rINTPND |= BIT_TIMER4;

 t--;

 t1--;

 div++;

 switch(div%2)

 {

  case 0:

   timer10ms();

   break;

  case 1:

   break;

  default:

   break;

 }

}

/***********************************************

Function  name  :   time4_init

Description: Timer 4 initialization

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/

void time4_init(unsigned int msec) //pass in 1

{

 volatile unsigned temp;

 temp=rTCFG0;

 temp&=~(0xf<<8);

 temp|=0xff<<8;

 rTCFG0=temp;

 temp=rTCFG1;

 temp&=~(0xf<<20|0xf<<16);

 temp|=0x2<<16;

 rTCFG1=temp; //Use 1/8 frequency

 msec=(msec==0)?1:msec; //Legal boundary value judgment

 rTCNTB4 = (50000*msec)>>11; //Set the timing count buffer value

 temp=rTCON;

 temp&=~(0x7<<20); //initialization

 temp|=1<<22|1<<21; // can automatically reload and redefine the value of TCNTB4

 rTCON=temp;

 rSRCPND|=BIT_TIMER4;

 rINTPND|=BIT_TIMER4;

 rINTMOD &=~BIT_TIMER4;

 rINTMSK &=~BIT_TIMER4;

 pISR_TIMER4 = (unsigned int)timer4_irq;

    temp = rTCON;

   temp &=~(0x7<<20);

   temp|=1<<22|1<<20;

   rTCON=temp;

}

/***********************************************

Function  name  :   timer10ms

Description: Timer processing function

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/

void timer10ms()

{

  (div10ms<=4)?(div10ms++):(div10ms=0); //0 1 2 3 4

  switch(div10ms)

  {

   case 0:

    break;

   case 1:

    break;

   case 2:

    break;

   case 3:

    break;

   case 4:

    break;

     default:

      break;

  }

}

/***********************************************

Function  name  :   timer0_irq

Description: Timer 0 interrupt service function

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/

static void  __irq timer0_irq(void)

{

 rSRCPND |= BIT_TIMER0;

    rINTPND |= BIT_TIMER0;

}

/***********************************************

Function  name  :   time0_stop

Description: Disable timer 0

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/

void time0_stop()

{

 volatile int temp;

 //1. Stop register

 rTCON &= ~(0x1<<0);

 //2.configure GPB0 to output and low level disable the pull up function

 temp = rGPBCON;

 temp &=~(0x3<<0);

 temp |= (0x1<<0);

 rGPBCON =temp;

 rGPBDAT &=~(0x1<<0);

 rGPBUP |=(0x1<<0); 

}

/***********************************************

Function  name  :   time0_init

Description: Timer 0 initialization

Input parameter :   none

Return          :   none   

Others      :   timer0 init                                      

*************************************************/

void time0_init(unsigned int nes)

{

 volatile unsigned temp;

 temp=rGPBCON;

 temp&=~(0x3);

 temp|=0x2;

 rGPBCON=temp;

 temp=rGPBUP;

 temp&=0;

 rGPBUP=temp;

 temp=rTCFG0;

 temp&=~(0xf);

 temp|=0xff;

 rTCFG0=temp;

 temp=rTCFG1;

 temp&=~(0xf<<20|0xf);//initialization

 temp|=0x2;

 rTCFG1=temp; //Use 1/8 frequency

 rTCNTB0 = (50000000/nes)>>11;

 rTCMPB0 = (50000000/nes)>>13;

 temp=rTCON;

 temp&=~(1<<3|1<<2|1<<1|1);

 temp|=1<<3|1<<1;

 rTCON=temp;

 rSRCPND|=BIT_TIMER0; 

 rINTMOD &=~BIT_TIMER0;

 rINTMSK &=~BIT_TIMER0;

 rINTPND|=BIT_TIMER0;

 pISR_TIMER0 = (unsigned int)timer0_irq;

 temp=rTCON;

 temp&=~(0xf);

 temp|=1<<3|1;

 rTCON=temp;

}

/***********************************************

Function  name  :   play_music

Description: Music playback function

Input parameter :   none

Return          :   none   

Others      :   none                                      

*************************************************/ 

void play_music(void)

{

 unsigned char ch;

 ch=uart_getc();

 while(1)

 {

  switch(ch)

  {

   case 'q':

   {

    time0_stop();

    time0_init(262);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'w':

   {

    time0_stop();

    time0_init(294);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'e':

   {

    time0_stop();

    time0_init(330);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'r':

   {

    time0_stop();

    time0_init(349);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 't':

   {

    time0_stop();

    time0_init(392);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'y':

   {

    time0_stop();

    time0_init(440);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'u':

   {

    time0_stop();

    time0_init(494);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'a':

   {

    time0_stop();

    time0_init(523);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 's':

   {

    time0_stop();

    time0_init(587);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'd':

   {

    time0_stop();

    time0_init(659);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'f':

   {

    time0_stop();

    time0_init(698);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'g':

   {

    time0_stop();

    time0_init(784);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'h':

   {

    time0_stop();

    time0_init(880);

    delays(1);

    time0_init(Syllable_freq[7]);

    break;

   }

   case 'j':

   {

    time0_stop();

    time0_init(988);

    delays(1);

    time0_init(Syllable_freq[7]);  // 1046,1175,1318,1397,1568,1760,1976

    break;

   }

   case 'z':

   {

    time0_stop();

    time0_init(1046);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   case 'x':

   {

    time0_stop();

    time0_init(1175);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   case 'c':

   {

    time0_stop();

    time0_init(1318);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   case 'v':

   {

    time0_stop();

    time0_init(1397);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   case 'b':

   {

    time0_stop();

    time0_init(1568);

    delays(1);

    time0_init(Syllable_freq[7]);  

    break;

   }

   case 'n':

   {

    time0_stop();

    time0_init(1760);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   case 'm':

   {

    time0_stop();

    time0_init(1976);

    delays(1);

    time0_init(Syllable_freq[7]); 

    break;

   }

   default:

    break;

  }

  ch=uart_getc();

 }

}