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| 1 | /* | |
| 2 | MultiBlinky v1.0 | |
| 3 | Blink 2 leds at different frequencies. | |
| 4 | The code is extremely verbose, to make it easier for beginners to | |
| 5 | understand what's happening. | |
| 6 | ||
| 7 | For future, as this sketch will eat cpu cycles as a starving donkey, | |
| 8 | I will add a microDelay at the end of the loop() function. Calculating | |
| 9 | the amount of microseconds to delay is the tricky part. Feel free to try | |
| 10 | your hand at it. | |
| 11 | */ | |
| 12 | ||
| 13 | /* | |
| 14 | Output leds | |
| 15 | */ | |
| 16 | #define LED1 13 | |
| 17 | #define LED2 12 | |
| 18 | ||
| 19 | /* | |
| 20 | How many cycles per second (how many cycles per 1000000 microseconds) | |
| 21 | are we doing? | |
| 22 | */ | |
| 23 | #define LED1_CYCLES 1 | |
| 24 | #define LED2_CYCLES 2 | |
| 25 | ||
| 26 | // these are here for clarity, you can define directly the microseconds/millisecond you need between HIGH/LOW | |
| 27 | uint32_t led1_period = 0; | |
| 28 | uint32_t led2_period = 0; | |
| 29 | ||
| 30 | // when did we last updated the led | |
| 31 | uint32_t led1_time; | |
| 32 | uint32_t led2_time; | |
| 33 | ||
| 34 | // state of the led | |
| 35 | char led1_state; | |
| 36 | char led2_state; | |
| 37 | ||
| 38 | void setup() | |
| 39 | {
| |
| 40 | pinMode(LED1, OUTPUT); | |
| 41 | pinMode(LED2, OUTPUT); | |
| 42 | ||
| 43 | // calculate here the period, so we don't have to do it on each loop() run. | |
| 44 | led1_period = 1000000/LED1_CYCLES; | |
| 45 | led2_period = 1000000/LED2_CYCLES; | |
| 46 | ||
| 47 | // initialize the system | |
| 48 | led1_state = LOW; | |
| 49 | led2_state = LOW; | |
| 50 | ||
| 51 | digitalWrite(LED1,LOW); | |
| 52 | digitalWrite(LED2,LOW); | |
| 53 | ||
| 54 | led1_time = 0; | |
| 55 | led2_time = 0; | |
| 56 | } // end function setup | |
| 57 | ||
| 58 | void loop() | |
| 59 | {
| |
| 60 | /* | |
| 61 | How many microseconds since the board was powered up. | |
| 62 | Arduino's internal timer will reset at some point and | |
| 63 | make our sketch miss a beat or two. If better timing | |
| 64 | is required, go on and use a RTC. | |
| 65 | */ | |
| 66 | uint32_t current_time = micros(); | |
| 67 | ||
| 68 | /* | |
| 69 | do we need to do anything to the first led? | |
| 70 | */ | |
| 71 | if ( current_time - led1_time > led1_period ) {
| |
| 72 | // switch the first led | |
| 73 | led1_time = current_time; | |
| 74 | if ( led1_state == LOW ) {
| |
| 75 | led1_state = HIGH; | |
| 76 | digitalWrite(LED1, led1_state); | |
| 77 | } else {
| |
| 78 | led1_state = LOW; | |
| 79 | digitalWrite(LED1, led1_state); | |
| 80 | } // end if | |
| 81 | } // end if | |
| 82 | ||
| 83 | /* | |
| 84 | do we need to do anything to the second led? | |
| 85 | */ | |
| 86 | if ( current_time - led2_time > led2_period ) {
| |
| 87 | // switch the first led | |
| 88 | led2_time = current_time; | |
| 89 | if ( led2_state == LOW ) {
| |
| 90 | led2_state = HIGH; | |
| 91 | digitalWrite(LED2, led2_state); | |
| 92 | } else {
| |
| 93 | led2_state = LOW; | |
| 94 | digitalWrite(LED2, led2_state); | |
| 95 | } // end if | |
| 96 | } // end if | |
| 97 | } // end function loop |
