This sketch is used by Exercise: Input Pattern Matching.
The full code is all in one file InputMatcher2.ino.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | // InputMatcher2.ino : Arduino program to demonstrate a simple finite state machine program structure.
// Copyright (c) 2014, Garth Zeglin. All rights reserved. Licensed under the terms
// of the BSD 3-clause license as included in LICENSE.
// The baud rate is the number of bits per second transmitted over the serial port.
const long BAUD_RATE = 115200;
// The state machine uses a single switch input.
const int INPUT_PIN = 4;
// Define the name for each state, and an index variable to represent the
// current state.
enum state_name_t { START = 0, STATE1, STATE2, STATE3 } state_index;
/****************************************************************/
/**** Standard entry points for Arduino system ******************/
/****************************************************************/
// Standard Arduino initialization function to configure the system.
void setup()
{
// initialize the Serial port
Serial.begin( BAUD_RATE );
// configure our trivial inputs
pinMode( INPUT_PIN, INPUT );
pinMode( LED_BUILTIN, OUTPUT );
// initialize the state machine
state_index = START;
}
/****************************************************************/
// Standard Arduino polling function.
// This demonstrates a conventional switch-case structure for representing a
// finite state machine as an Arduino program. The current state is represented
// as the value of the state_index variable. Note that this structure allows
// for easily evaluating other subroutines or state machines concurrently with
// this one, as the execution passes through the loop() function on each
// iteration.
void loop()
{
// select the code block corresponding to the state to generate the appropriate outputs for the state
switch( state_index) {
case START:
Serial.println("Entering start state.");
digitalWrite(LED_BUILTIN, LOW);
break;
case STATE1:
Serial.println("Entering state 1.");
digitalWrite(LED_BUILTIN, LOW);
break;
case STATE2:
Serial.println("Entering state 2.");
digitalWrite(LED_BUILTIN, LOW);
break;
case STATE3:
Serial.println("Entering state 3.");
digitalWrite(LED_BUILTIN, HIGH);
break;
}
delay(1000);
Serial.println("Sampling input.");
int input = digitalRead( INPUT_PIN );
// select the code block corresponding to the current state to evaluate the next input
switch( state_index) {
case START:
if (input) state_index = STATE1;
else state_index = START;
break;
case STATE1:
if (input) state_index = START;
else state_index = STATE2;
break;
case STATE2:
if (input) state_index = STATE3;
else state_index = STATE1;
break;
case STATE3:
if (input) state_index = STATE3;
else state_index = START;
break;
}
}
/****************************************************************/
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