main.c

   1 #include <stdio.h>
   2 #include <wiringPi.h>
   3 #include <time.h>
   4 #include "config.h"
   5 #define COIN_BUTTON 7
   6
   7 configuration config;
   8 int expires = -1;
   9 int one_second_ago = 0;
  10
  11 void init_gpio()
  12 {
  13   wiringPiSetup();
  14   pinMode(COIN_BUTTON, INPUT);
  15   pullUpDnControl(COIN_BUTTON, PUD_UP);
  16 }
  17
  18 int now()
  19 {
  20   return (unsigned)time(NULL);
  21 }
  22
  23 int time_over()
  24 {
  25   if(one_second_ago != now() && expires != -1)
  26   {
  27     printf("You have %d seconds remaining\n", expires - now());
  28     one_second_ago = now();
  29   }
  30
  31   if(expires == now())
  32   {
  33     printf("It's all ogre now\n");
  34     expires = -1;
  35     return 1;
  36   }
  37
  38   return expires == -1;
  39 }
  40
  41 int read_button()
  42 {
  43   if(digitalRead(COIN_BUTTON) == LOW)
  44   {
  45     printf("Nice! I just added %d to your time.\n", config.credit_value);
  46
  47     //Increment timer
  48     if(expires == -1) //Initial credit, set the expiry to now plus time
  49     {
  50         expires = now() + config.credit_value;
  51     } else { //expiry already set, simply extend by time
  52         expires += config.credit_value;
  53     }
  54
  55     //wait for button to be released
  56     while(digitalRead(COIN_BUTTON) == LOW)
  57     {
  58        //I don't see this happening, but in principle if the button is held down
  59        //It would be possible to stop the switch happening after time runs out
  60        //So we must check for that here.
  61        if(time_over())
  62          break;
  63
  64        delay(10);
  65     }
  66
  67     return 1;
  68   }
  69
  70   return 0;
  71 }
  72
  73 int main (void)
  74 {
  75   init_config(&config);
  76   init_gpio();
  77
  78   printf ("Short pin 7 and 9 to increment timer.\n") ;
  79
  80   while(1)
  81   {
  82     read_button();
  83     //I don't really need to call this here but I'm doing it to see output.
  84     time_over();
  85     delay(10);
  86   }
  87 }