#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>
#include <ncurses.h> /* libncurses5-dev */

/*
PCF8591PG.c

Instalar curses:

sudo apt-get install libncurses5-dev

Compilar:

gcc -o PCF8591PG PCF8591PG.c -lcurses -lpigpio -lpthread

Run:

sudo ./PCF8591
*/

/*
Connect Pi 3V3 - VCC, Ground - Ground, SDA - SDA, SCL - SCL.
*/

#define PCF8591_I2C_ADDR 0x48

/*
    P4 The thermister voltage is provided at AIN 2.
    P5 The photocell voltage is provided at AIN 1.
    P6 The single turn 10K ohm trim pot voltage is provided at AIN 0.
*/

/*
7 6 5 4 3 2 1 0
0 X X X 0 X X X
  | | |   | | |
  A B B   C D D

0 1 0 0 0 1 0 0

A 0 D/A inactive
  1 D/A active

B 00 single ended inputs
  01 differential inputs
  10 single ended and differential
  11 two differential inputs

C 0 no auto inc
  1 auto inc

D 00 select channel 0
  01 select channel 1
  10 select channel 2
  11 select channel 3

*/

int main(int argc, char *argv[])
{
   int i;
   int r;
   int handle;
   unsigned char command;
   unsigned char value[4];
   unsigned char str[8];
   char *filename = (char*)"/dev/i2c-1";

   int j;
   int key;

   if (gpioInitialise() < 0) return 1;

   initscr();
   noecho();
   nodelay(stdscr, true);
   curs_set(0);

   printw("PCF8591, any key to quit.");

   mvaddstr(10, 0, "Resistor");
   mvaddstr(12, 0, "Brightness");
   mvaddstr(14, 0, "Temperature");
   mvaddstr(16, 0, "GND");

   refresh();

   handle = i2cOpen(1, PCF8591_I2C_ADDR, 0);


   while (1)
   {
      for (i=0; i<4; i++)
      {
         command = 0x40 | ((i+1) & 0x03); // habilita la salida | selecciona el canal de lectura i

         i2cWriteDevice(handle, &command, 1);	//escribe la palabra de control

         usleep(20000);

         value[i] = i2cReadByte(handle);	//lee los datos de la entrada seleccionada

         sprintf(str, "%3d", value[i]);		//imprime en pantalla el valor leido
         mvaddstr(10+i+i, 12, str);
         value[i] = value[i] / 4;
         move(10 + i + i, 16);

         for(j = 0; j < 64; j++)
            if(j < value[i]) addch('*'); else addch(' ');
      }

      refresh();

      key = getch();

      if  (key != -1)                   break;
   }

   endwin();
 
   i2cClose(handle);

   gpioTerminate();

   return (0);
}