adc.c

lpc2478+ucosII

/*****************************************************************************
 *   adc.c:  ADC module file for NXP LPC23xx Family Microprocessors
 *
 *   Copyright(C) 2006, NXP Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2006.08.15  ver 1.00    Prelimnary version, first Release
 *
******************************************************************************/
#include "LPC2468.h"                        /* LPC23xx definitions */
#include "type.h"
#include "irq.h"
#include "target.h"
#include "adc.h"

volatile DWORD ADC0Value[ADC_NUM];
volatile DWORD ADC0IntDone = 0;

#if ADC_INTERRUPT_FLAG
/******************************************************************************
** Function name:		ADC0Handler
**
** Descriptions:		ADC0 interrupt handler
**
** parameters:			None
** Returned value:		None
**
******************************************************************************/
__irq __arm void ADC0Handler (void)
{
    DWORD regVal;

    __enable_interrupt();			/* handles nested interrupt */

    regVal = AD0STAT;		/* Read ADC will clear the interrupt */
    if ( regVal & 0x0000FF00 )	/* check OVERRUN error first */
    {
	    regVal = (regVal & 0x0000FF00) >> 0x08;
	    /* if overrun, just read ADDR to clear */
	    /* regVal variable has been reused. */
	    switch ( regVal )
	    {
	      case 0x01:
			regVal = AD0DR0;
		  break;
	      case 0x02:
			regVal = AD0DR1;
		  break;
	      case 0x04:
			regVal = AD0DR2;
		  break;
	      case 0x08:
			regVal = AD0DR3;
		  break;
	      case 0x10:
			regVal = AD0DR4;
		  break;
	      case 0x20:
			regVal = AD0DR5;
		  break;
	      case 0x40:
			regVal = AD0DR6;
		  break;
	      case 0x80:
			regVal = AD0DR7;
		  break;
	      default:
		  break;
	    }
	    AD0CR &= 0xF8FFFFFF;	/* stop ADC now */
	    ADC0IntDone = 1;
	    return;	
    }

    if ( regVal & ADC_ADINT )
    {
	    switch ( regVal & 0xFF )	/* check DONE bit */
	    {
	      case 0x01:
			ADC0Value[0] = ( AD0DR0 >> 6 ) & 0x3FF;
	      break;
	      case 0x02:
			ADC0Value[1] = ( AD0DR1 >> 6 ) & 0x3FF;
	      break;
	      case 0x04:
			ADC0Value[2] = ( AD0DR2 >> 6 ) & 0x3FF;
	      break;
	      case 0x08:
			ADC0Value[3] = ( AD0DR3 >> 6 ) & 0x3FF;
	      break;
	      case 0x10:
			ADC0Value[4] = ( AD0DR4 >> 6 ) & 0x3FF;
	      break;
	      case 0x20:
			ADC0Value[5] = ( AD0DR5 >> 6 ) & 0x3FF;
	      break;
	      case 0x40:
			ADC0Value[6] = ( AD0DR6 >> 6 ) & 0x3FF;
	      break;
	      case 0x80:
			ADC0Value[7] = ( AD0DR7 >> 6 ) & 0x3FF;
	      break;		
	      default:
	      break;
	    }
	    AD0CR &= 0xF8FFFFFF;	/* stop ADC now */
	    ADC0IntDone = 1;
    }

    __disable_interrupt();
    VICVectAddr = 0;		/* Acknowledge Interrupt */
}
#endif

/*****************************************************************************
** Function name:		ADCInit
**
** Descriptions:		initialize ADC channel
**
** parameters:			ADC clock rate
** Returned value:		true or false
**
*****************************************************************************/
DWORD ADCInit( DWORD ADC_Clk )
{
    /* Enable CLOCK into ADC controller */
    PCONP |= (1 << 12);

    /* all the related pins are set to ADC inputs, AD0.0~7 */
    PINSEL0 |= 0x0F000000;	/* P0.12~13, A0.6~7, function 11 */	
    PINSEL1 &= ~0x003FC000;	/* P0.23~26, A0.0~3, function 01 */
    PINSEL1 |= 0x00154000;
    PINSEL3 |= 0xF0000000;	/* P1.30~31, A0.4~5, function 11 */

    AD0CR = ( 0x01 << 0 ) | 	/* SEL=1,select channel 0~7 on ADC0 */
		( ( Fpclk / ADC_Clk - 1 ) << 8 ) |  /* CLKDIV = Fpclk / 1000000 - 1 */
		( 0 << 16 ) | 		/* BURST = 0, no BURST, software controlled */
		( 0 << 17 ) |  		/* CLKS = 0, 11 clocks/10 bits */
		( 1 << 21 ) |  		/* PDN = 1, normal operation */
		( 0 << 22 ) |  		/* TEST1:0 = 00 */
		( 0 << 24 ) |  		/* START = 0 A/D conversion stops */
		( 0 << 27 );		/* EDGE = 0 (CAP/MAT singal falling,trigger A/D conversion) */

    /* If POLLING, no need to do the following */
#if ADC_INTERRUPT_FLAG
    AD0INTEN = 0x1FF;		        /* Enable all interrupts */
    if ( install_irq( ADC0_INT, (void *)ADC0Handler, HIGHEST_PRIORITY ) == FALSE )
    {
	    return (FALSE);
    }
#endif
    return (TRUE);
}

/*****************************************************************************
** Function name:		ADC0Read
**
** Descriptions:		Read ADC0 channel
**
** parameters:			Channel number
** Returned value:		Value read, if interrupt driven, return channel #
**
*****************************************************************************/
DWORD ADC0Read( BYTE channelNum )
{
#if !ADC_INTERRUPT_FLAG
    DWORD regVal, ADC_Data;
#endif

    /* channel number is 0 through 7 */
    if ( channelNum >= ADC_NUM )
    {
	    channelNum = 0;		/* reset channel number to 0 */
    }
    AD0CR &= 0xFFFFFF00;
    AD0CR |= (1 << 24) | (1 << channelNum);	
				/* switch channel,start A/D convert */
#if !ADC_INTERRUPT_FLAG
    while ( 1 )			/* wait until end of A/D convert */
    {
	    regVal = *(volatile unsigned long *)(AD0_BASE_ADDR
			+ ADC_OFFSET + ADC_INDEX * channelNum);
				/* read result of A/D conversion */
	    if ( regVal & ADC_DONE )
	    {
		    break;
	    }
    }	

    AD0CR &= 0xF8FFFFFF;	/* stop ADC now */
    if ( regVal & ADC_OVERRUN )	/* save data when it's not overrun, otherwise, return zero */
    {
	    return ( 0 );
    }
    ADC_Data = ( regVal >> 6 ) & 0x3FF;   /* 数据使用的是15:6共10个bit，10位有效 */
    return ( ADC_Data );	/* return A/D conversion value */
#else
    return ( channelNum );	/* if it's interrupt driven, the ADC reading is
							done inside the handler. so, return channel number */
#endif
}

/*********************************************************************************
**                            End Of File
*********************************************************************************/