a2d.c

TI 集成高性能24位A/D转换器的8052 核心单片机MSC1210 A/D转换代码。

//
// Copyright 2003 Texas Instruments
// author: Russell Anderson
//
// A/D Conversion
// Integer test of A/D Converter
//
#include <REG1210.H>
#include <stdio.h>
#define SET    1
#define RESET  0
#define CLEAR  0

extern void autobaud(void);
extern long bipolar(void);

sbit Sync = P1^4; 
void dacout (unsigned int val)
{
	Sync = SET;			// Sync pulse
	Sync = CLEAR;
	// Note: To avoid SPI overflow, sufficient delay between 
	//		every 3 SPIDATA write is needed.
	SPIDATA = 0; 		// Normal DAC Mode
	SPIDATA = (char)(val>>8 & 0x00ff);
	SPIDATA = (char)(val & 0x00ff);;		
}

void main(void)
{
	signed long int data result, dummy, average, max, min;
	int k, samples, decimation, pga, gain, j;

	CKCON = 0; 						// 0 MOVX cycle stretch
	PDCON = 0x14;					// turn on ADC-Vref, SPI and Systimers
/* SPI setup */
	SPICON = 0x06;					// SCLK=tclk/2, Double-Buf Mode, Order=MSB, Master, CPHA=1, CPOL=0
	SPITCON = 0x28;				// Enable SCLK, Enable MOSI	

	autobaud();
	printf("\nMSC1210 ADC Conversion Test\n\n");
	printf("Gain    Dec.   rate      Ave Value       Max-Min     Max       Min\n");

/* Setup ADC */
	ADMUX = 0x08;					//(AIN+ = AIN0),  (AIN- = AINCOM) Voltage from DAC
	ACLK = 9;						// ACLK = 11,0592,000/10 = 1,105,920 Hz
										// modclock = 1,105,920/64 = 17,280 Hz
	samples=15;
	gain = 0;
	for (pga=0; pga<8 ; pga++)	// PGA Loop
	{	
		dacout(0x4000>>pga);		// Set DAC to 1/4 full-scale
		gain = gain*2;
		gain = gain ? gain : 1;
		ADCON0 = 0x30 | pga;		// Vref On, Vref Hi, Buff off, BOD off, pga
		for (decimation=90; decimation<=2070; decimation+=90)	// decimation loop
		{
			ADCON2 = decimation & 0xFF;		// LSB of decimation
			ADCON3 =(decimation>>8) & 0x07;	// MSB of decimation
			ADCON1 = 0x01;							// bipolar, auto, self calibration (offset, gain)
			for (k=0; k<4; k++) {				// Wait for Four conversions for filter to settle after calibration
				while (!(AIE & 0x20))	
					;									// Wait for data ready
				dummy = bipolar();				// Dummy read to clear ADCIRQ
			}
			max = 0; min = 0x7FFFFFFF;
			average = 0;
			for (j = 0; j < samples; j++){
				while (!(AIE & 0x20))
					{} 								// Wait for next result
				result = bipolar(); 
				average += result;
				max = (max > result) ? max : result;
				min = (min < result) ? min : result;
			}
			average = average/samples;			// Divide by 8
			printf ("%3d,%7d,%6dHz,", gain,decimation,17280/decimation);		// 17280 = ACLK/64
			printf ("%12ld,  %10ld, %8ld,", average, max-min, max);
			printf ("  %8ld\n",min);			// One printf() can't handle all of these variables.
		}// for decimation loop
	} // PGA loop
	printf("\n FINISHED \n-----------\n");
	while(1)
		;
} //main