Multiple Switches, One Interrupt

1// Ron Bentley, Stafford UK
2// September 2021
3//
4// This example  and code is in the public domain and may be used without
5// restriction and without  warranty.
6//
7// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
8//         Example sketch - Multiple switches handled by a single interrupt
9//         '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
10// This  sketch demonstrates how the ez_switch_lib may be used to handle multiple
11// switches  (button & toggle switches in this example)with a single interrupt routine.
12//
13//  The use of the ez_switch_lib library for switches provides:
14//   * switch type  independence
15//   * switch circuit type independence
16//   * automatic multiple  switch debounce handling
17//   * parallel switching capabilities, and
18//   *  automatic interrupt handling for all switches
19//
20// The sketch will use digital  pin 2 as the common interrupt pin and
21// pins 3, 4, 5, 6, 7 and 8 as the switch  pins.
22//
23// For an understanding of the full capabilities of the 'ez_switch_lib'  library see
24// the USER GUIDE:
25// https://github.com/ronbentley1/ez_switch_lib-Arduino-Library/blob/main/ez_switch_lib_user_guide%2C%20v1.04.pdf
26//
27//  or a synopsis CRIB SHEET:
28// https://github.com/ronbentley1/ez_switch_lib-Arduino-Library/blob/main/ez_switch_lib%20crib%20sheet.pdf
29//  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
30
31#include  <ez_switch_lib.h>          // declare the switch library
32
33#define common_interrupt_pin    2   // external (common) interrupt pin that all declared switches will use
34
35#define  num_switches            6   // number of switches the sketch will declare & use
36
37Switches  my_switches(num_switches); // create the 'Switches' instance for the given number  of switches
38
39// Declare the data required for each of our switches, 'my_switch_data':
40//  'my_switch_data' layout, one row of data for each switch to be configured,
41//  as follows:
42// [][0] = switch type (button_switch or toggle_switch)
43// [][1]  = digital pin connected to switch
44// [][2] = the circuit type connecting the  switch, here the first 3 switches
45//         will have 10k ohm pull down resistors  wired (circuit_C1 - INPUT type)
46//         and the remainder none (circuit_C2  - INPUT_PULLUP type).
47byte my_switch_data[][3] =
48{
49  toggle_switch,  3,  circuit_C1, // this will be the switch entry for switch_id 0
50  toggle_switch,  4, circuit_C1, // this will be the switch entry for switch_id 1
51  toggle_switch,  5, circuit_C1, // etc
52  button_switch,  6, circuit_C2,
53  button_switch,  7, circuit_C2,
54  button_switch,  8, circuit_C2,
55};
56
57void setup() {
58  int result;
59  Serial.begin(115200);
60  // Add all switches to the library  switch control structure we defined above
61  // and link all switches to the same  interrupt pin as a linked output
62  for (uint8_t switch_id = 0; switch_id < num_switches;  switch_id++) {
63    result = my_switches.add_switch(
64               my_switch_data[switch_id][0],  // switch type
65               my_switch_data[switch_id][1],  // digital pin  switch is wired to
66               my_switch_data[switch_id][2]); // type of circuit  switch is wired as
67    // Check that we have successfully added the current switch  or not
68    if (result < 0) {
69      // No slots left or bad parameters
70      Serial.println("*** Failure to add switch.\
71 Terminated");
72      Serial.flush();
73      exit(0);
74    }
75    // now make the linkage for this switch_id to the  common interrupt pin
76    result = my_switches.link_switch_to_output(
77               switch_id,             // switch to be linked
78               common_interrupt_pin,  //  digital pin to link to for interrupt
79               LOW);                  //  start with interrupt pin LOW, as interrupt will be triggered on RISING
80    //  Check that we have successfully linked the current switch or not
81    if (result  < 0) {
82      // Could not link the given switch
83      Serial.println("***  Failure to link switch.\
84 Terminated");
85      Serial.flush();
86      exit(0);
87    }
88  }
89  // set debounce period
90  my_switches.set_debounce(150);  //  can be reduced if you have good quality switches
91  // Now establish the common  interrupt service routine (ISR) that
92  // will be used for all declared switches.
93  attachInterrupt(
94    digitalPinToInterrupt(common_interrupt_pin),
95    switch_ISR,  // name of the sketch's ISR handler for switch interrupts
96    RISING);    //  trigger on a rising pin value
97} // end of setup function
98
99void loop() {
100  // Keep testing switches, and let the interrupt handler do its thing
101  // once  a switch is switched to 'on'
102  // We use 'read_switch' function as this deals  with both switch types for us transparently.
103  for (uint8_t switch_id = 0; switch_id  < num_switches; switch_id++) {
104    if (my_switches.read_switch(switch_id) ==  switched) {
105      // *** Add any code here, if any, to process this switch as  it has been actuated.
106      // *** This is in addition to whatever the ISR does  following the triggering
107      // *** of the interrupt, if this switch has been  linked to the common interrupt pin.
108
109    }
110  }
111}
112
113// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
114//  Common ISR for handling interrupt triggers arising from associated switches
115//  when they transition to on then off for button switches and on or off
116// for  toggle switches.  The routine knows which switch has generated
117// the interrupt  because the ez_switch_lib switch read function records the
118// actuated switch  in the library variable 'last_switched_id'.
119//
120// The routine does nothing  more than demonstrate the effectiveness of the
121// use of a single ISR handling  multiple switches by using the serial monitor
122// to confirm correct operation.
123//  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
124void  switch_ISR()
125{
126  // Reset the interrupt pin to LOW, so that any other switch  will fire the
127  // interrupt whist one or more switches complete their transition  stage
128  byte switch_id = my_switches.last_switched_id;  // switch id of switch  currently switched
129  digitalWrite(my_switches.switches[switch_id].switch_out_pin,  LOW);
130  // Reset the soft status of the switch setting to ensure that we get  an interrupt event
131  // on the linked interrupt pin at next switch change
132  my_switches.switches[switch_id].switch_out_pin_status = LOW;
133  Serial.print("**  Interrupt triggered for switch id: ");
134  Serial.print(switch_id); // the id  of the last triggering switch
135  if (my_switches.switches[switch_id].switch_type  == button_switch) {
136    // this was a button switch triggering the interrupt
137    // *** Button switch processing
138    // *** Put end user code here to deal  with this event
139
140    Serial.println(".. button switch..switched");
141  }  else {
142    // this was a toggle switch triggering the interrupt
143    // determine  if the switch transitioned to 'on' or 'off'
144    // and process accordingly
145    Serial.print(".. toggle switch.. ");
146    if (my_switches.switches[switch_id].switch_status  == on) {
147      // *** Toggle switch processing for switch being 'on'
148      //  *** Put end user code here to deal with this event
149
150      Serial.println("is  on");
151    } else {
152      // *** Toggle switch processing for switch being  'off'
153      // *** Put end user code here to deal with this event
154
155      Serial.println("is  off");
156    }
157  }
158  Serial.flush();
159} // end of switch_ISR
160