Charles Tritt / Mbed OS 21_WhatTime_v5

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main.cpp@110:a930767c281c, 2021-10-01 (annotated)

Committer:
CSTritt
Date:
Fri Oct 01 03:05:20 2021 +0000
Revision:
110:a930767c281c
Parent:
109:b061f9830736
Child:
111:2b4b5da72a15
First Mbed v. 5 version.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
CSTritt 107:61b9c99a4e27 1 /*
CSTritt 110:a930767c281c 2 Project: 21_TimerTest2_v5
CSTritt 109:b061f9830736 3 File: main.cpp
CSTritt 110:a930767c281c 4
CSTritt 110:a930767c281c 5 Tests timer peformance. Display new time difference with each button press
CSTritt 110:a930767c281c 6 and release. Differences of 4 or 5 microseconds are typical.
CSTritt 109:b061f9830736 7
CSTritt 110:a930767c281c 8 Last modified 9/30/21 by C. S. Tritt (v. 1.0)
CSTritt 107:61b9c99a4e27 9 */
Jonathan Austin 0:2757d7abb7d9 10 #include "mbed.h"
CSTritt 110:a930767c281c 11
CSTritt 110:a930767c281c 12 // Construct a USER_BUTTON digital input.
CSTritt 110:a930767c281c 13 DigitalIn myButton(USER_BUTTON);
CSTritt 110:a930767c281c 14
CSTritt 110:a930767c281c 15 // Construct a timer object.
CSTritt 110:a930767c281c 16 Timer myTimer;
CSTritt 110:a930767c281c 17
CSTritt 110:a930767c281c 18 // Construct a transmit only serial connection over our USB.
CSTritt 110:a930767c281c 19 Serial pc(USBTX, NC, 9600);
CSTritt 110:a930767c281c 20
CSTritt 109:b061f9830736 21 int main()
CSTritt 109:b061f9830736 22 {
CSTritt 110:a930767c281c 23 myTimer.start(); // Start the timer.
CSTritt 110:a930767c281c 24
CSTritt 109:b061f9830736 25 while(true) { // Main loop.
CSTritt 110:a930767c281c 26 if (myButton == 0) { // Button is pressed (active low).
CSTritt 110:a930767c281c 27 // Save the time on timer.
CSTritt 110:a930767c281c 28 int firstTime = myTimer.read_us();
CSTritt 110:a930767c281c 29 int secondTime = myTimer.read_us();
CSTritt 110:a930767c281c 30
CSTritt 110:a930767c281c 31 // Send the time as text via the serial port.
CSTritt 110:a930767c281c 32 pc.printf("Time difference %i microseconds.\n", secondTime -
CSTritt 110:a930767c281c 33 firstTime );
CSTritt 110:a930767c281c 34
CSTritt 110:a930767c281c 35 // Reset the timer.
CSTritt 110:a930767c281c 36 myTimer.reset();
CSTritt 110:a930767c281c 37
CSTritt 110:a930767c281c 38 // Wait for the user to release the button.
CSTritt 110:a930767c281c 39 while(myButton == 0) {
CSTritt 110:a930767c281c 40 }
CSTritt 108:eee3167b25b4 41 }
CSTritt 108:eee3167b25b4 42 }
CSTritt 108:eee3167b25b4 43 }