hello_2pwm.c

NIOS环境PWM的USER LOGIC实例1

/****************************************************************************************/
/* Copyright ?2004 Altera Corporation, San Jose, California, USA. All rights reserved. */
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/* This agreement shall be governed in all respects by the laws of the State of         */
/* California and by the laws of the United States of America.  Altera does not         */
/* recommend, suggest or require that this reference design file be used in conjunction */
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/****************************************************************************************/

//Includes
#include <stdio.h>

#include "system.h"
#include "altera_avalon_pio_regs.h"
#include "alt_types.h"

#include "altera_avalon_pwm_routines.h"

//Function Protypes
void print_error(unsigned int address, int return_code);
void check_return_code(unsigned int address, int return_code);

int main(void)

{
 
 unsigned int duty_cycle;
 int return_code = ALTERA_AVALON_PWM_OK;
 
 printf("Hello from the Altera Avalon PWM.\n");
 printf("See Flashing LED3,LED4 on the ezNiosDK board.\n");
 
 //Initialize PWM and Check Return Code
 return_code = init_Altera_Avalon_PWM(AVALON_SLAVE_PWM_0_BASE,500000,1);
 return_code = init_Altera_Avalon_PWM(AVALON_SLAVE_PWM_1_BASE,500000,490000);
 check_return_code(AVALON_SLAVE_PWM_0_BASE, return_code);
 check_return_code(AVALON_SLAVE_PWM_1_BASE, return_code);
 
 //Enable PWM and Check Return Code
 return_code = enable_Altera_Avalon_PWM(AVALON_SLAVE_PWM_0_BASE); 
 return_code = enable_Altera_Avalon_PWM(AVALON_SLAVE_PWM_1_BASE);
 check_return_code(AVALON_SLAVE_PWM_0_BASE, return_code);
 check_return_code(AVALON_SLAVE_PWM_1_BASE, return_code);

//init duty_cycle with the value written to duty_cycle register during initialization
 duty_cycle = *ALTERA_AVALON_PWM_DUTY_CYCLE(AVALON_SLAVE_PWM_0_BASE);  
 
 
 
 while(1)
   {

     while(duty_cycle++ < *ALTERA_AVALON_PWM_CLOCK_DIVIDER(AVALON_SLAVE_PWM_0_BASE))
     {
        return_code = change_Altera_Avalon_PWM_Duty_Cycle(AVALON_SLAVE_PWM_0_BASE, duty_cycle); 
        check_return_code(AVALON_SLAVE_PWM_0_BASE, return_code);
        return_code = change_Altera_Avalon_PWM_Duty_Cycle(AVALON_SLAVE_PWM_1_BASE, 500000 - duty_cycle); 
        check_return_code(AVALON_SLAVE_PWM_1_BASE, return_code);
     }          
     while(--duty_cycle > 1)
     {
        return_code = change_Altera_Avalon_PWM_Duty_Cycle(AVALON_SLAVE_PWM_0_BASE, duty_cycle);
        check_return_code(AVALON_SLAVE_PWM_0_BASE, return_code);
        change_Altera_Avalon_PWM_Duty_Cycle(AVALON_SLAVE_PWM_1_BASE, 500000 - duty_cycle);
        check_return_code(AVALON_SLAVE_PWM_1_BASE, return_code);
     }
   }
return 0;
}

void check_return_code(unsigned int address, int return_code)
{
  if(return_code != ALTERA_AVALON_PWM_OK)
         print_error(address, return_code);  
}

void print_error(unsigned int address, int return_code)
{
 printf("Program Terminated Due to an error with Avalon PWM located at 0x%x:\n", address);
 switch(return_code)
 {
 case ALTERA_AVALON_PWM_DUTY_CYCLE_GREATER_THAN_CLOCK_CYCLE_ERROR:
   printf("The value in the clock cycle register must be greater than the value in the duty cycle register\n");
    printf("Value in the Clock Divide Register: 0x%x\n", *ALTERA_AVALON_PWM_CLOCK_DIVIDER(address)); 
   printf("Value in the Duty Cycle Register: 0x%x\n", *ALTERA_AVALON_PWM_DUTY_CYCLE(address));
   break;
        case ALTERA_AVALON_PWM_ENABLED_CONFIRMATION_ERROR:
                printf("Unable to confirm that the PWM is enabled\n");
    printf("Value in the Enable Register: 0x%x\n", *ALTERA_AVALON_PWM_ENABLE(address)); 
          break;
        case ALTERA_AVALON_PWM_DISABLED_CONFIRMATION_ERROR:
         printf("Unable to confirm that the PWM is disabled\n");
   printf("Value in the Enable Register: 0x%x\n", *ALTERA_AVALON_PWM_ENABLE(address)); 
          break;
        default:
          break;         
 }

while(1);
}
// end of file