mcp3208.c

Mega16 + MCP3208 12bit A/D >> C-source code >> AVRSTUDIO project >> WinAVR

#include <avr/io.h>
#include "mcp3208.h"


void MCP3208_spiDelay(unsigned int NOPcount)
{
	unsigned int n;
	for(n=0;n<=NOPcount;n++)
	{
		asm volatile ("nop" ::);
	}
}

void MCP3208_spiInit(void)
{
    // Set MOSI, SCK and ENB output, all other input
    DDR_SPI = (1<<DD_MOSI)|(1<<DD_SCK)|(1<<DD_SS);  // set DD_SS to output

    // Enable SPI, Master, set clock rate fclk/64 
	// Setup (Falling) Sample (Rising) SPI set mode 3 
	// CPOL=1 : CPHA=1
	SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR1)|(0<<SPR0)|(1<<CPOL)|(1<<CPHA);
	PORT_SPI |= (1<<(PIN_CS));    //setbitHigh CS   Pin
	PORT_SPI |= (1<<(PIN_MOSI));  //setbitHigh MOSI Pin
	PORT_SPI |= (1<<(PIN_CLK));   //setbitHigh CLK  Pin
}

unsigned char MCP3208_spiWrite(char cData)
{        
    // Start transmission
    SPDR = cData;                   
    // Wait for transmission complete
    while (!(SPSR & (1<<SPIF)))   
        ;
    return SPDR;
}

unsigned int MCP3208_spiRead(unsigned char AD_type,unsigned char ADchanel)
{
	unsigned char  tempHigh,tempLow,tempADtype,dumyData;

    PORT_SPI &= ~(1<<(PIN_CS));     //setbitLow CS  Pin
	MCP3208_spiDelay(delayCount );

	tempADtype = (AD_type & 0x01) << 1 ;
	tempLow = (ADchanel & 0x03) << 6;	
    tempHigh = (ADchanel & 0x04) >> 2;	
	tempHigh |= (0x04)|(tempADtype);     // 0x04 --> startBit

	dumyData = MCP3208_spiWrite(tempHigh);  	  // Write control HighByte return not care
    gReciveHighByte = MCP3208_spiWrite(tempLow);  // Write control LowByte return A/D-MSB data
    gReciveLowByte = MCP3208_spiWrite(0x00);      // Write Null byte 0x00 return A/D-LSB data

	MCP3208_spiDelay(delayCount );
    PORT_SPI |= (1<<(PIN_CS));	    //setbitHigh CS  Pin

	return (((gReciveHighByte & 0x0F)<<8)|gReciveLowByte);  // return 16bit variable (12bit A/D data)
}