xtest17_2.c

AT91sam7s 256 B/D example

/* ========================================================================== */
/*	       Xtest17_2.c : A/D Conversion of AD5 Input for VR1	      */
/* ========================================================================== */
/*			  Designed and programmed by Duck-Yong Yoon in 2007.  */

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

void LCD_4hex(unsigned int number)		/* display 4-digit hex number */
{ unsigned int i;

  i = number >> 12;                             // 16^3
  if(i <= 9) LCD_data(i + '0');
  else       LCD_data(i - 10 + 'A');

  i = (number >> 8) & 0x000F;                   // 16^2
  if(i <= 9) LCD_data(i + '0');
  else       LCD_data(i - 10 + 'A');

  i = (number >> 4) & 0x000F;                   // 16^1
  if(i <= 9) LCD_data(i + '0');
  else       LCD_data(i - 10 + 'A');

  i = number & 0x000F;                          // 16^0
  if(i <= 9) LCD_data(i + '0');
  else       LCD_data(i - 10 + 'A');
}

void LCD_1d2(float number)		        /* floating-point number x.xx */
{ unsigned int i, j;

  j = (int)(number*100. + 0.5);
  i = j / 100;					// 10^0
  LCD_data(i + '0');
  LCD_data('.');

  j = j % 100;					// 10^-1
  i = j / 10;
  LCD_data(i + '0');

  i = j % 10;					// 10^-2
  LCD_data(i + '0');
}

int main(void)
{ unsigned int i, sum;

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

  LCD_string(0x80,"    AD5(VR1)    ");		// display title
  LCD_string(0xC0,"0x0000 = 0.00[V]");
  Beep();

  AT91F_ADC_CfgPMC();				// enable peripheral clock for ADC
  AT91F_ADC_SoftReset(AT91C_BASE_ADC);		// clear all previous ADC settings
  *AT91C_ADC_MR = 0x02020400;			// SHTIM=2 (sample & hold time = 625ns)
						// STARTUP=2 (startup time = 5us)
						// 4.8MHz, 10 bit, software trigger
  AT91F_ADC_EnableChannel(AT91C_BASE_ADC, AT91C_ADC_CH5); // select CH5 for VR1

  while(1)
    { sum = 0;
      for(i=0; i<32; i++)
        { AT91F_ADC_StartConversion(AT91C_BASE_ADC); // start conversion
          while(!(AT91F_ADC_GetStatus(AT91C_BASE_ADC) & AT91C_ADC_EOC5)); // wait for EOC
          sum += AT91F_ADC_GetConvertedDataCH5(AT91C_BASE_ADC); // add A/D result 32 times
          Delay_ms(1);
        }
      sum >>= 5;				// divide sum by 32 for average value

      LCD_command(0xC2);                        // display in HEX
      LCD_4hex(sum);
      LCD_command(0xC9);                        // display voltage(x.xx)
      LCD_1d2((float)sum*3.3/1024.);		// voltage = sum*3.3/1024

      Delay_ms(250);                            // delay 250 ms
    }
}