Jatin Sharma / Mbed 2 deprecated CIS541-HW3

Basic timer on mBed 1768

Dependencies:   TextLCD mbed

Fork of HelloWorld by Simon Ford

main.cpp@2:253054128736, 2014-09-28 (annotated)

Committer:
jatinsha
Date:
Sun Sep 28 03:02:57 2014 +0000
Revision:
2:253054128736
Parent:
0:fb6bbc10ffa0
Child:
3:d18d3609c800
timer with Start, Pause/Unpause and Reset ; 24ms error (slow) in 3.9 seconds

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jatinsha 2:253054128736 1 /*
jatinsha 2:253054128736 2 CIS 541 - Embedded Systems for Life Critical Applications
jatinsha 2:253054128736 3 Assignment3
jatinsha 2:253054128736 4 Timer using mBed 1768
jatinsha 2:253054128736 5
jatinsha 2:253054128736 6 Developers - Jatin Sharma and Samarth Shah
jatinsha 2:253054128736 7
jatinsha 2:253054128736 8 References
jatinsha 2:253054128736 9 1. Timer : http://mbed.org/handbook/Timer
jatinsha 2:253054128736 10 2. String format modifiers : http://www.cdf.toronto.edu/~ajr/209/notes/printf.html
jatinsha 2:253054128736 11 3. Keyboard Input : http://mbed.org/handbook/SerialPC
jatinsha 2:253054128736 12 4. Interrupt attach : http://mbed.org/handbook/Serial
jatinsha 2:253054128736 13 5. Enum tutorial : http://stackoverflow.com/questions/1102542/how-to-define-an-enumerated-type-enum-in-c
jatinsha 2:253054128736 14 6.
jatinsha 2:253054128736 15
jatinsha 2:253054128736 16 */
jatinsha 2:253054128736 17
simon 0:fb6bbc10ffa0 18
jatinsha 2:253054128736 19 #include "mbed.h"
jatinsha 2:253054128736 20 #include "TextLCD.h"
jatinsha 2:253054128736 21
jatinsha 2:253054128736 22 // RS, E, D4 - D7 for 4 bit mode
jatinsha 2:253054128736 23 #define RS p15
jatinsha 2:253054128736 24 #define E p16
jatinsha 2:253054128736 25 #define D4 p17
jatinsha 2:253054128736 26 #define D5 p18
jatinsha 2:253054128736 27 #define D6 p19
jatinsha 2:253054128736 28 #define D7 p20
jatinsha 2:253054128736 29 #define interval 10
jatinsha 2:253054128736 30
jatinsha 2:253054128736 31 TextLCD lcd(RS, E, D4, D5, D6, D7, TextLCD::LCD16x2);
jatinsha 2:253054128736 32 Timer timerDisplay, timerReference;
jatinsha 2:253054128736 33 Serial pc(USBTX, USBRX); // tx, rx
jatinsha 2:253054128736 34
jatinsha 2:253054128736 35 int miliSeconds, centiSeconds, seconds, minutes;
jatinsha 2:253054128736 36 int currentReferenceTime, previousReferenceTime;
jatinsha 2:253054128736 37 int calculatedTimeInterval, referenceTimeInterval, runningError;
jatinsha 2:253054128736 38 char keyboardInput;
simon 0:fb6bbc10ffa0 39
jatinsha 2:253054128736 40 typedef enum {Running, Paused, Reset} state_t;
jatinsha 2:253054128736 41 state_t timerState = Reset;
jatinsha 2:253054128736 42
jatinsha 2:253054128736 43 void callback()
jatinsha 2:253054128736 44 {
jatinsha 2:253054128736 45 // Keyboard input : you need to actually read from the serial to clear the RX interrupt
jatinsha 2:253054128736 46 if(keyboardInput = pc.getc())
jatinsha 2:253054128736 47 {
jatinsha 2:253054128736 48 if((keyboardInput == 's' || keyboardInput == 'S'))
jatinsha 2:253054128736 49 {
jatinsha 2:253054128736 50 if(timerState == Reset)
jatinsha 2:253054128736 51 {
jatinsha 2:253054128736 52 timerReference.start();
jatinsha 2:253054128736 53 timerDisplay.start();
jatinsha 2:253054128736 54 timerState = Running;
jatinsha 2:253054128736 55 }
jatinsha 2:253054128736 56 }
jatinsha 2:253054128736 57 if((keyboardInput == 'p' || keyboardInput == 'P'))
jatinsha 2:253054128736 58 {
jatinsha 2:253054128736 59 if(timerState == Running)
jatinsha 2:253054128736 60 {
jatinsha 2:253054128736 61 timerReference.stop();
jatinsha 2:253054128736 62 timerDisplay.stop();
jatinsha 2:253054128736 63 timerState = Paused;
jatinsha 2:253054128736 64 }
jatinsha 2:253054128736 65 else if(timerState == Paused)
jatinsha 2:253054128736 66 {
jatinsha 2:253054128736 67 timerReference.start();
jatinsha 2:253054128736 68 timerDisplay.start();
jatinsha 2:253054128736 69 timerState = Running;
jatinsha 2:253054128736 70 }
jatinsha 2:253054128736 71 }
jatinsha 2:253054128736 72 if((keyboardInput == 'r' || keyboardInput == 'R'))
jatinsha 2:253054128736 73 {
jatinsha 2:253054128736 74 if(timerState == Paused)
jatinsha 2:253054128736 75 {
jatinsha 2:253054128736 76 // Reset timer
jatinsha 2:253054128736 77 timerReference.reset();
jatinsha 2:253054128736 78 timerDisplay.reset();
jatinsha 2:253054128736 79 timerState = Reset;
jatinsha 2:253054128736 80
jatinsha 2:253054128736 81 // Reset variables
jatinsha 2:253054128736 82 miliSeconds = seconds = minutes = 0;
jatinsha 2:253054128736 83 currentReferenceTime = previousReferenceTime = 0;
jatinsha 2:253054128736 84 calculatedTimeInterval = referenceTimeInterval = runningError = 0;
jatinsha 2:253054128736 85 lcd.locate(0,0);
jatinsha 2:253054128736 86 lcd.printf("00:00:00");
jatinsha 2:253054128736 87 lcd.locate(0,1);
jatinsha 2:253054128736 88 lcd.printf("000000");
jatinsha 2:253054128736 89 }
jatinsha 2:253054128736 90 }
simon 0:fb6bbc10ffa0 91 }
jatinsha 2:253054128736 92 }
jatinsha 2:253054128736 93
jatinsha 2:253054128736 94 int main()
jatinsha 2:253054128736 95 {
jatinsha 2:253054128736 96 // interrupt service routine
jatinsha 2:253054128736 97 pc.attach(&callback);
jatinsha 2:253054128736 98
jatinsha 2:253054128736 99 // local variable
jatinsha 2:253054128736 100 miliSeconds = seconds = minutes = 0;
jatinsha 2:253054128736 101 currentReferenceTime = previousReferenceTime = 0;
jatinsha 2:253054128736 102 calculatedTimeInterval = referenceTimeInterval = runningError = 0;
jatinsha 2:253054128736 103 //timerReference.start();
jatinsha 2:253054128736 104 //timerDisplay.start();
jatinsha 2:253054128736 105
jatinsha 2:253054128736 106 // Initial display work
jatinsha 2:253054128736 107 lcd.locate(0,0);
jatinsha 2:253054128736 108 lcd.printf("00:00:00");
jatinsha 2:253054128736 109
jatinsha 2:253054128736 110 while(1)
jatinsha 2:253054128736 111 {
jatinsha 2:253054128736 112 if( timerDisplay.read_ms() >= interval)
jatinsha 2:253054128736 113 {
jatinsha 2:253054128736 114 timerDisplay.reset();
jatinsha 2:253054128736 115
jatinsha 2:253054128736 116 // Calculate display variables
jatinsha 2:253054128736 117 miliSeconds += interval;
jatinsha 2:253054128736 118
jatinsha 2:253054128736 119 centiSeconds += (miliSeconds / 10);
jatinsha 2:253054128736 120 miliSeconds %= 10;
jatinsha 2:253054128736 121
jatinsha 2:253054128736 122 seconds += (centiSeconds / 100);
jatinsha 2:253054128736 123 centiSeconds %= 100;
jatinsha 2:253054128736 124
jatinsha 2:253054128736 125 minutes += (seconds / 60);
jatinsha 2:253054128736 126 seconds %= 60;
jatinsha 2:253054128736 127
jatinsha 2:253054128736 128 // Error correction using referenceClock
jatinsha 2:253054128736 129 currentReferenceTime = timerReference.read_us();
jatinsha 2:253054128736 130 referenceTimeInterval = currentReferenceTime - previousReferenceTime;
jatinsha 2:253054128736 131 runningError += (referenceTimeInterval - interval*1000);
jatinsha 2:253054128736 132
jatinsha 2:253054128736 133 //miliSeconds += runningError;
jatinsha 2:253054128736 134 previousReferenceTime = currentReferenceTime;
jatinsha 2:253054128736 135
jatinsha 2:253054128736 136
jatinsha 2:253054128736 137 // Display time on LCD
jatinsha 2:253054128736 138 lcd.locate(0,0);
jatinsha 2:253054128736 139 lcd.printf("%02d:%02d:%02d",minutes, seconds, centiSeconds);
jatinsha 2:253054128736 140
jatinsha 2:253054128736 141 lcd.locate(0,1);
jatinsha 2:253054128736 142 lcd.printf("%06d", runningError);
jatinsha 2:253054128736 143 }
jatinsha 2:253054128736 144
jatinsha 2:253054128736 145
jatinsha 2:253054128736 146
jatinsha 2:253054128736 147
jatinsha 2:253054128736 148
jatinsha 2:253054128736 149 }
jatinsha 2:253054128736 150
simon 0:fb6bbc10ffa0 151 }