/* Temperature logger based on PIC18F4550                    */

#include <stdio.h>   /* Standard input/output definitions    */
#include <string.h>  /* String function definitions          */
#include <unistd.h>  /* UNIX standard function definitions   */
#include <fcntl.h>   /* File control definitions             */
#include <errno.h>   /* Error number definitions             */
#include <termios.h> /* POSIX terminal control definitions   */

#define Rsize 56
#define Half Rsize/2
#define Nchan 13

int fd;
unsigned char Word[Rsize];
unsigned char *Wpt;

int Count = 0;

int InitPort(void)
  {
    struct termios options;

    fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);


    if (fd == -1)
      {
        fputs("Unable to open port\n", stdout);
        return 0;
      }
    else
      {
        tcgetattr(fd, &options);

        cfsetispeed(&options, B57600);        /* Set the input  baud rate   */
        cfsetospeed(&options, B57600);        /* Set the output baud rate   */

        options.c_cflag |= (CLOCAL | CREAD); /* Enable receiver, set local */

        options.c_cflag &= ~PARENB;          /* Clear parity enable        */
        options.c_cflag &= ~CSTOPB;          /* Remove 2nd stop bit        */
        options.c_cflag &= ~CSIZE;           /* Clear data length          */
        options.c_cflag |= CS8;              /* Character size = 8 bits    */

        options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);  /* RAW input  */
        options.c_oflag &= ~OPOST;                           /* RAW output */

        options.c_cflag &= ~CRTSCTS;      /* Disable hardware flow control */

        tcsetattr(fd, TCSANOW, &options);    /* set attributes immediately */;

        return 1;
      }
  }


void ReadPort(void)
  {
    int i;
    for (i=0; i<Rsize; i++) Word[i] = 0;

    Wpt = Word;
    read(fd, Wpt, Rsize);
  }



int GetTemp(void)
  {
    int i = 0;

    unsigned char Head;
    unsigned char Term;

    int ADRESH;
    int ADRESL;
    int ADRESM;

    int DataOK = 0;
    int Pointer;

    int  Tmp[Nchan];
    int Temp[Nchan];
    int Stat[Nchan];

    while(i<Half)
      {
        Head = Word[i];
	Term = Word[i+Half-1];
	if ((Head==0xA0) && (Term==0x40))
	 {
	   DataOK = 1;
           Pointer = i;
	   break;
	 };
	i++;
      }

    if (! DataOK) return 0;

    Wpt = &Word[Pointer];


/* Raw ADC values */

    for (i=0; i<Nchan; i++)
       {
         ADRESH = (int)*(++Wpt);
	 ADRESL = (int)*(++Wpt);

	 ADRESM = (ADRESH & 0x1C)<<3;
         ADRESH = (ADRESH & 0x03)<<8;

         Tmp[i] = ADRESH | ADRESM | ADRESL;
       }

/* Mapping and pedestal subtraction */

    Temp[0]  = Tmp[7]  - Tmp[2];
    Temp[1]  = Tmp[6]  - Tmp[2];
    Temp[2]  = Tmp[5]  - Tmp[2];
    Temp[3]  = Tmp[4]  - Tmp[2];
    Temp[4]  = Tmp[3]  - Tmp[2];
    Temp[5]  = Tmp[1]  - Tmp[2];
    Temp[6]  = Tmp[0]  - Tmp[2];
    Temp[7]  = Tmp[11] - Tmp[2];
    Temp[8]  = Tmp[9]  - Tmp[2];
    Temp[9]  = Tmp[8]  - Tmp[2];
    Temp[10] = Tmp[10] - Tmp[2];
    Temp[11] = Tmp[12] - Tmp[2];
    Temp[12] = Tmp[2];


/* Averaging over 1000 samples*/

    if (Count == 1000) Count = 0;
    if (Count == 0)
       {
         printf("new 1k sample\n");
         for (i=0; i<Nchan; i++) Stat[i] = 0;
       }

    Count++;

    for (i=0; i<Nchan; i++) Stat[i] += Temp[i];

    printf("%d: ", Count);
    for (i=0; i<Nchan; i++) printf(" %d  ", Stat[i]/Count);
    printf("\n");

    return 1;
  }



int main(void)
{

  if (!InitPort()) return 0;


  while(1)
     {
       ReadPort();
       GetTemp();
       usleep(10000);
     }
  close(fd);
  return 1;
}