xtest12_3.c

AT91sam7s 256 B/D example

/* ========================================================================== */
/*	Xtest12_3.c : Variable Period and Duty Cycle of PWM0 Output	      */
/* ========================================================================== */
/*			  Designed and programmed by Duck-Yong Yoon in 2007.  */

#include "AT91SAM7S256.h"
#include "lib_AT91SAM7S256.h"
#include "OK7S256ads.h"

void LCD_3d(unsigned int number)		/* display 3-digit decimal number */
{ unsigned int i, flag;

  flag = 0;
  i = number/100;				// 10^2
  if(i == 0) LCD_data(' ');
  else {     LCD_data(i + '0');
             flag = 1;
       }

  number = number % 100;			// 10^1
  i = number/10;
  if((i == 0) && (flag == 0))
             LCD_data(' ');
  else {     LCD_data(i + '0');
             flag = 1;
       }

  i = number % 10;				// 10^0
  LCD_data(i + '0');
}

void LCD_2d(unsigned int number)		/* display 2-digit decimal number */
{ unsigned int i;

  i = number/10;				// 10^1
  if(i == 0) LCD_data(' ');
  else       LCD_data(i + '0');

  i = number % 10;				// 10^0
  LCD_data(i + '0');
}

__inline void AT91F_PWMC_CfgMode(
        AT91PS_PWMC pPWM,			// pointer to a PWM controller
        unsigned int mode)			// PWM_MR register value
{
	pPWM->PWMC_MR = mode;
}

int main(void)
{
  unsigned int PWM0_period = 100, PWM0_duty = 10; // initial PWM period and duty value
  unsigned int step = 10;			// initial PWM duty step
  unsigned int flag = 0;			// new setting flag
  double current_duty;				// current duty cycle

  MCU_initialize();				// initialize AT91SAM7S256 & kit
  Delay_ms(50);					// wait for system stabilization
  LCD_initialize();				// initialize text LCD

  LCD_string(0x80,"PWM0 Freq & Duty");		// display title
  LCD_string(0xC0," 100/100kHz,10% ");
  Beep();

  AT91F_PWMC_CfgPMC();				// enable clock of PWMC
  AT91F_PIO_CfgPeriph(AT91C_BASE_PIOA, AT91C_PA0_PWM0, 0);
  						// PWM0 output(Peripheral A)

  AT91F_PWMC_CfgMode(AT91C_BASE_PWMC, 0x041E041E); // CLKA=CLKB = 48MHz/16/30 = 100kHz
  AT91F_PWMC_CfgChannel(AT91C_BASE_PWMC, 0, 0x020B, 100, PWM0_duty); // CLKA/100 = 1kHz
  AT91F_PWMC_StartChannel(AT91C_BASE_PWMC, AT91C_PWMC_CHID0); // start PWM0

  while(1)
    { switch(Key_input())
        { case 1 : PWM0_duty += step;		// increment PWM0 duty by 10%
                   if(PWM0_duty == PWM0_period)
                     PWM0_duty = step;
                   flag = 1;
                   break;
          case 2 : current_duty = (double)PWM0_duty / (double)PWM0_period;
                   PWM0_period += 100;		// increment PWM0 period by 100
                   if(PWM0_period == 1000)
                     PWM0_period = 100;
		   PWM0_duty = current_duty * (double)PWM0_period + 0.5;
                   step = PWM0_period / 10;	// calculate new duty step
                   flag = 2;
                   break;
          default: flag = 0;
                   break;
        }

      if(flag == 1)
        { flag = 0;
          *AT91C_PWMC_CH0_CMR &= ~AT91C_PWMC_CPD; // update duty cycle
          AT91F_PWMC_UpdateChannel(AT91C_BASE_PWMC, 0, PWM0_duty);
          LCD_command(0xCC);			// display PWM0 duty cycle
          LCD_2d(PWM0_duty*100/PWM0_period);
        }
      else if(flag == 2)
        { flag = 0;
          if(PWM0_duty > *AT91C_PWMC_CH0_CPRDR)
            { while(!(*AT91C_PWMC_ISR & AT91C_PWMC_CHID0));
              *AT91C_PWMC_CH0_CMR |= AT91C_PWMC_CPD;  // update period
              AT91F_PWMC_UpdateChannel(AT91C_BASE_PWMC, 0, PWM0_period);
              while(!(*AT91C_PWMC_ISR & AT91C_PWMC_CHID0));
              *AT91C_PWMC_CH0_CMR &= ~AT91C_PWMC_CPD; // update duty cycle
              AT91F_PWMC_UpdateChannel(AT91C_BASE_PWMC, 0, PWM0_duty);
            }
          else
            { while(!(*AT91C_PWMC_ISR & AT91C_PWMC_CHID0));
              *AT91C_PWMC_CH0_CMR &= ~AT91C_PWMC_CPD; // update duty cycle
              AT91F_PWMC_UpdateChannel(AT91C_BASE_PWMC, 0, PWM0_duty);
              while(!(*AT91C_PWMC_ISR & AT91C_PWMC_CHID0));
              *AT91C_PWMC_CH0_CMR |= AT91C_PWMC_CPD;  // update period
              AT91F_PWMC_UpdateChannel(AT91C_BASE_PWMC, 0, PWM0_period);
            }
          LCD_command(0xC5);			// display PWM0 period and duty
          LCD_3d(PWM0_period);
          LCD_command(0xCC);
          LCD_2d(PWM0_duty*100/PWM0_period);
        }
    }
}