/*
 * Success version
 * gcc mcp3002.c -omcp3002 -lwiringPi -DMCP3002
 * Read MCP3002/MCP3204 using wiringPiSPIDataRW
 */
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <wiringPi.h>
#include <wiringPiSPI.h>
using namespace std;

#define DEBUG 0
#define SPI_CHANNEL 0 // /dev/spidev0.0
//#define SPI_CHANNEL 1 // /dev/spidev0.1

int main(int argc, char **argv){
    int retCode;
    int i;
    int a2dChannel = 0;  // analog channel
    int a2dVal = 0;
    float a2dVol = 0;
    float Vref = 3.3;
#ifdef MCP3002
    unsigned char data[2];
#endif
#ifdef MCP3204
    unsigned char data[3];
#endif

    if (argc == 2) {
        cout << "argv[1]=",argv[1],"\n";
        a2dChannel=atoi(argv[1]);
    }

// SPI channel 0 を 1MHz で開始。 =>200k
    if (wiringPiSPISetup(SPI_CHANNEL, 200000) < 0)
    {
        cout << "SPISetup failed:\n";
    }

    for(i=0;i<20;i++) {
#ifdef MCP3002
        data[0] = 0b01100000 |( ((a2dChannel & 0x03) << 4));  //  first byte transmitted -> start bit
        data[1] = 0; // third byte transmitted....don't care
if(DEBUG) cout << "[MCP3002]data[write]=" << hex << data[0] << "-" << hex << data[1] <<"\n";
        retCode=wiringPiSPIDataRW (SPI_CHANNEL,data,sizeof(data));
if(DEBUG) cout << "[MCP3002]wiringPiSPIDataRW=" << retCode << "\n";
if(DEBUG) cout << "[MCP3002]data[read]=" << hex << data[0] << "-" << hex << data[1] << "\n";
        a2dVal = (data[0]<< 8) & 0b1100000000; //first 2 bit
        a2dVal |=  (data[1] & 0xff);
        a2dVol = (float)a2dVal/1023 * Vref;
#endif
#ifdef MCP3204
        data[0] = 0b00000110 |( ((a2dChannel & 0x04) >> 2));  //  first byte transmitted -> start bit -> (SGL/DIF = 1, D2=0)
        data[1] = 0b00000000 |( ((a2dChannel & 0x03) << 6)); // second byte transmitted -> (D1=D0=0)
        data[2] = 0; // third byte transmitted....don't care
if(DEBUG) cout << "[MCP3204]data[write]=" << hex << data[0] << "-" << hex << data[1] << "\n";
        retCode=wiringPiSPIDataRW (SPI_CHANNEL,data,sizeof(data));
if(DEBUG) cout << "[MCP3004]wiringPiSPIDataRW=" << retCode << "\n";
if(DEBUG) cout << "[MCP3204]data[read]=" << hex << data[0] << "-" << hex << data[1] << "-" << hex << data[2];
        a2dVal = (data[1]<< 8) & 0b111100000000; //first 4 bit
        a2dVal |=  (data[2] & 0xff);
        a2dVol = (float)a2dVal/4095 * Vref;
#endif

        cout << "a2dVal=" << a2dVal << "\n";
        cout << "a2dVol=" << a2dVol << "[V]\n";
        sleep(1);
    }
}