main.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <wiringPi.h>
   5 #include <time.h>
   6 #include "config.h"
   7
   8 #define COIN_BUTTON 7 //physically pin 7
   9 #define SYNC_PIN 4 //physically pin 16
  10 #define PULSE_PIN 1 //physically pin 12
  11
  12 configuration config;
  13 int expires = -1;
  14 int one_second_ago = 0;
  15 int switch_state; //Keeps track of what state the software thinks the switch should be in
  16
  17 void init_gpio()
  18 {
  19   wiringPiSetup();
  20   pinMode(COIN_BUTTON, INPUT);
  21   pinMode(SYNC_PIN, INPUT);
  22   pinMode(PULSE_PIN, OUTPUT);
  23   digitalWrite(PULSE_PIN, 0); //just to be sure
  24
  25   pullUpDnControl(COIN_BUTTON, PUD_UP);
  26   pullUpDnControl(SYNC_PIN, PUD_UP);
  27 }
  28
  29 void pulse_switch()
  30 {
  31   delay(config.sync_switch_delay); //wait
  32   digitalWrite(PULSE_PIN, 1);
  33   delay(100);
  34   digitalWrite(PULSE_PIN, 0);
  35   delay(100);
  36 }
  37
  38 int validate_switch_state()
  39 {
  40   if(config.sync_switch == 0 || digitalRead(SYNC_PIN) == switch_state)
  41     return 1;
  42
  43   printf("Sync pin is not what I expected, attempting to switch signal\n");
  44   pulse_switch();
  45
  46   return digitalRead(SYNC_PIN) == switch_state;
  47 }
  48
  49 int now()
  50 {
  51   return (unsigned)time(NULL);
  52 }
  53
  54 int time_over()
  55 {
  56   if(one_second_ago != now() && expires != -1)
  57   {
  58     printf("You have %d seconds remaining\n", expires - now());
  59     one_second_ago = now();
  60   }
  61
  62   if(expires != -1 && expires <= now())
  63   {
  64     printf("It's all ogre now\n");
  65     expires = -1;
  66     switch_state = 1 - switch_state;
  67
  68     if(config.sync_switch == 0) //naively pulse
  69       pulse_switch();
  70
  71     return 1;
  72   }
  73
  74   return expires == -1;
  75 }
  76
  77 int read_button()
  78 {
  79   // In the case of an external timer all we need to do is set the internal switch
  80   // state to match the state of the external timer pin. Low means a they can see
  81   // the second input, high means show the default video.
  82   if(config.external_timer == 1)
  83   {
  84     if(digitalRead(COIN_BUTTON) == HIGH)
  85     {
  86       switch_state = config.default_switch_state;
  87     } else {
  88       switch_state = 1 - config.default_switch_state;
  89     }
  90
  91     return 1;
  92   } else {
  93     if(digitalRead(COIN_BUTTON) == LOW)
  94     {
  95       // Don't do anything until button is released
  96       while(digitalRead(COIN_BUTTON) == LOW)
  97       {
  98         //I don't see this happening, but in principle if the button is held down
  99         //It would be possible to stop the switch happening after time runs out
 100         //So we must check for that here.
 101         time_over();
 102         delay(10);
 103       }
 104
 105       // Flip internal switch state, but only if we are in the default state
 106       // i.e., waiting for a credit
 107       if(config.default_switch_state == switch_state)
 108       {
 109         printf("Changing internal switch state from %d\n", switch_state);
 110         switch_state = 1 - switch_state;
 111         printf("Switch state is now %d\n", switch_state);
 112
 113         if(config.sync_switch == 0) //naively pulse the switch
 114             pulse_switch();
 115       }
 116
 117       printf("Nice! I just added %d to your time.\n", config.credit_value);
 118
 119       //Increment timer
 120       if(expires == -1) //Initial credit, set the expiry to now plus time
 121       {
 122           expires = now() + config.credit_value;
 123       } else { //expiry already set, simply extend by time
 124           expires += config.credit_value;
 125       }
 126
 127       return 1;
 128     }
 129   }
 130
 131   return 0;
 132 }
 133
 134 int main (int argc, char *argv[])
 135 {
 136   if(argc == 2 && strcmp("version", argv[1]) == 0)
 137   {
 138     printf("hdmi-switcher %s\n", VERSION);
 139     exit(1);
 140   }
 141
 142   init_config(&config);
 143   init_gpio();
 144   switch_state = config.default_switch_state;
 145   printf ("Short pin 7 and 9 to increment timer.\n") ;
 146
 147   while(1)
 148   {
 149     if(validate_switch_state() == 0)
 150     {
 151       printf("Unable to switch video signal. Exiting.\n");
 152       exit(1);
 153     }
 154
 155     read_button();
 156     //I don't really need to call this here but I'm doing it to see output.
 157     time_over();
 158     delay(10);
 159   }
 160
 161   exit(0);
 162 }