LPC1114 用定时器驱动的ADC转换

/************************************************************************
*** Copyright(c) 2011, by XH Du.  ******

*** Filename: LPC11xx_ADC_user.c
*** Current Version: 1.0
*** Complete Date: 2011-4-21

***   Fuction: Timer32_0 driver to ADC
************************************************************************/
#include  "LPC11xx.h"
#include  "LPC11xx_ADC_user.h"

#define  ADCTIMER_MAT (SystemAHBFrequency/800 - 1)   //  Timer 10ms SystemAHBFrequency = 48MHZ

#define ADC_ADINT  0x00010000
#define ADC_CLK   1000000  /* set to 1Mhz */

void init()
{
 ADCInit( ADC_CLK );
}

/******************************************************************************
** Function name:  ADC_IRQHandler
**
** Descriptions:  ADC interrupt handler
**
** parameters:   None
** Returned value:  None
**
******************************************************************************/
void ADC_IRQHandler (void)
{

 uint32_t regVal;

 regVal = LPC_ADC->STAT;  /* Read ADC will clear the interrupt */

 if ( regVal & 0x0000FF00 ) /* check OVERRUN error first  */
  {
  regVal = (regVal & 0x0000FF00) >> 0x08;
  switch ( regVal )
   {
   case 0x01:
      regVal = LPC_ADC->DR[0];
      break;
   case 0x02:
      regVal = LPC_ADC->DR[1];
      break;
   case 0x04:
      regVal = LPC_ADC->DR[2];
      break;
   case 0x08:
      regVal = LPC_ADC->DR[3];
      break;
   case 0x10:
      regVal = LPC_ADC->DR[4];
      break;
   case 0x20:
      regVal = LPC_ADC->DR[5];
      break;
   case 0x40:
      regVal = LPC_ADC->DR[6];
      break;
   case 0x80:
      regVal = LPC_ADC->DR[7];
      break;
   default:
      break;
   }
  }

 if ( regVal & ADC_ADINT )
  {
  switch ( regVal & 0xFF ) /* check DONE bit */
   {
   case 0x01:
      regVal = ( LPC_ADC->DR[0] >> 6 ) & 0x3FF;  // read ADC value
      break;

   case 0x02:
      regVal = ( LPC_ADC->DR[1] >> 6 ) & 0x3FF;
      break;

   case 0x04:
      regVal = ( LPC_ADC->DR[2] >> 6 ) & 0x3FF;
      break;

   case 0x08:
      regVal = ( LPC_ADC->DR[3] >> 6 ) & 0x3FF;
      break;
   default:
      break;
   }
  }
}

/*****************************************************************************
** Function name:  ADCInit
**
** Descriptions:  initialize ADC channel
**
** parameters:   ADC clock rate
** Returned value:  None
*****************************************************************************/
void ADCInit( uint32_t ADC_Clk)
{
 /* Disable Power down bit to the ADC block.   ADC Power UP*/
 LPC_SYSCON->PDRUNCFG &= ~(0x1<<4);

 /* Enable AHB clock to the ADC. */
 LPC_SYSCON->SYSAHBCLKCTRL |= (1<<13);

 LPC_IOCON->JTAG_TDI_PIO0_11    &= ~0x9F; /* Clear bit7, change to analog mode. Clear bit4-3,remove pull-up/pull down resistor*/
 LPC_IOCON->JTAG_TDI_PIO0_11    |= 0x02;  /* Select ADC IN0 */
 LPC_IOCON->JTAG_TMS_PIO1_0   &= ~0x9F; /* Clear bit7, change to analog mode. */
 LPC_IOCON->JTAG_TMS_PIO1_0   |= 0x02;  /* ADC IN1 */
 LPC_IOCON->JTAG_TDO_PIO1_1   &= ~0x9F; /* Clear bit7, change to analog mode. */
 LPC_IOCON->JTAG_TDO_PIO1_1   |= 0x02;  /* ADC IN2 */
 LPC_IOCON->JTAG_nTRST_PIO1_2   &= ~0x9F; /* Clear bit7, change to analog mode. */
 LPC_IOCON->JTAG_nTRST_PIO1_2   |= 0x02;  /* ADC IN3 */

 LPC_ADC->CR = ((SystemAHBFrequency / ADC_Clk - 1 ) << 8 );  /* CLKDIV = Fpclk / 1000000 - 1 */

 NVIC_EnableIRQ(ADC_IRQn);
 LPC_ADC->INTEN = 0x00F;  /* Enable all interrupts */

 LPC_ADC->CR &= ~(( 0x01 << 17 ) | ( 1 << 18 ) | ( 1 << 19 ) | /* CLKS = 0, 11 clocks/10 bits */
                                 ( 1 << 24 ) | ( 1 << 25 ) | ( 1 << 16 ));  /* START = 0 A/D conversion stops  BURST=0*/

 /*  Channel select CH-0,1,2,3,7, BURST = 1,  hardware controlled   26-24: 100 Timer320-MAT0 , 27:1 MAT0 Falling edge*/
 LPC_ADC->CR |= ((0x01<<0) | ( 0x1 << 1 ) | ( 1 << 2 ) | ( 1 << 3 ) | ( 1 << 26 ) | (1<<27));  /*   Start conversion when the falling edge on  CT32B0_MAT0*/

 ADCTimerInit(ADCTIMER_MAT);  //  Timer

}

 

/******************************************************************************
** Function name:  init_timer
**
** Descriptions:  Initialize timer, set timer interval, reset timer,
**      install timer interrupt handler
**
** parameters:   timer interval
** Returned value:  None
**
******************************************************************************/
void ADCTimerInit(uint32_t MATInterval)
{
 LPC_SYSCON->SYSAHBCLKCTRL |= (1<<9);  /* Enable AHB clock to the Timer32-0. */

 LPC_TMR32B0->PR  = 0x07;  /* set prescaler to 8   SystemAHBFrequency/8 = 6MHZ*/

 LPC_TMR32B0->MR0 = MATInterval;  // Match value  (SystemAHBFrequency/800)*(1/6M) = 10ms

 LPC_TMR32B0->EMR &= ~(0xFF<<4);
 LPC_TMR32B0->EMR |= (0x3<<4);    /* Timer32_0_MAT0  Match 0 driver adc*/

 LPC_TMR32B0->MCR |= (0x01<<1);    /*  Match Reset on MR0 */

 EnableADCTimer();
}

/******************************************************************************
** Function name:  EnableADCTimer
**
** Descriptions:  Enable timer
**
** parameters:   None
** Returned value:  None
**
******************************************************************************/
void EnableADCTimer(void)
{
    LPC_TMR32B0->TCR = 1;
}

/******************************************************************************
** Function name:  DisableADCTimer
**
** Descriptions:  Disable timer
**
** parameters:   None
** Returned value:  None
**
******************************************************************************/
void DisableADCTimer(void)
{
    LPC_TMR32B0->TCR = 0;
}