Stage-1 Students SoCEM / Mbed 2 deprecated Task443Solution

Task 4.3.3 Solution

Dependencies:   mbed

main.cpp@0:5c5a623dc9e0, 2015-09-24 (annotated)

Committer:
noutram
Date:
Thu Sep 24 12:31:08 2015 +0000
Revision:
0:5c5a623dc9e0
Initial version 24-09-2015

Who changed what in which revision?

UserRevisionLine numberNew contents of line
noutram 0:5c5a623dc9e0 1 #include "mbed.h"
noutram 0:5c5a623dc9e0 2
noutram 0:5c5a623dc9e0 3 //Function prototype
noutram 0:5c5a623dc9e0 4 void doSample1Hz();
noutram 0:5c5a623dc9e0 5 void printBinary12(unsigned short u16);
noutram 0:5c5a623dc9e0 6
noutram 0:5c5a623dc9e0 7 //Global objects
noutram 0:5c5a623dc9e0 8 Serial pc(USBTX, USBRX);
noutram 0:5c5a623dc9e0 9 AnalogIn POT_ADC_In(A0);
noutram 0:5c5a623dc9e0 10 DigitalOut led(LED1);
noutram 0:5c5a623dc9e0 11
noutram 0:5c5a623dc9e0 12 //Shared variables
noutram 0:5c5a623dc9e0 13 volatile static unsigned short sample16 = 0;
noutram 0:5c5a623dc9e0 14
noutram 0:5c5a623dc9e0 15 //The ticker, used to sample data at a fixed rate
noutram 0:5c5a623dc9e0 16 Ticker t;
noutram 0:5c5a623dc9e0 17
noutram 0:5c5a623dc9e0 18 //Main function
noutram 0:5c5a623dc9e0 19 int main()
noutram 0:5c5a623dc9e0 20 {
noutram 0:5c5a623dc9e0 21 //Set baud rate to 115200
noutram 0:5c5a623dc9e0 22 pc.baud(115200);
noutram 0:5c5a623dc9e0 23
noutram 0:5c5a623dc9e0 24 //Set up the ticker - 100Hz
noutram 0:5c5a623dc9e0 25 t.attach(doSample1Hz, 1.0);
noutram 0:5c5a623dc9e0 26
noutram 0:5c5a623dc9e0 27 while(1) {
noutram 0:5c5a623dc9e0 28
noutram 0:5c5a623dc9e0 29 //Sleep
noutram 0:5c5a623dc9e0 30 sleep();
noutram 0:5c5a623dc9e0 31
noutram 0:5c5a623dc9e0 32 //Displauy the sample in HEX
noutram 0:5c5a623dc9e0 33 printBinary12(sample16);
noutram 0:5c5a623dc9e0 34
noutram 0:5c5a623dc9e0 35 } //end while(1)
noutram 0:5c5a623dc9e0 36 } //end main
noutram 0:5c5a623dc9e0 37
noutram 0:5c5a623dc9e0 38 //ISR for the ticker - simply there to perform sampling
noutram 0:5c5a623dc9e0 39 void doSample1Hz()
noutram 0:5c5a623dc9e0 40 {
noutram 0:5c5a623dc9e0 41 //Toggle on board led
noutram 0:5c5a623dc9e0 42 led = !led;
noutram 0:5c5a623dc9e0 43
noutram 0:5c5a623dc9e0 44 //READ ADC as an unsigned integer.
noutram 0:5c5a623dc9e0 45 //Shift right 4 bits (this is a 12bit ADC) & store in static global variable
noutram 0:5c5a623dc9e0 46 sample16 = POT_ADC_In.read_u16() >> 4;
noutram 0:5c5a623dc9e0 47 }
noutram 0:5c5a623dc9e0 48
noutram 0:5c5a623dc9e0 49 //Function to print a 12-bit number in the binary format
noutram 0:5c5a623dc9e0 50 //(I've kept this simple to avoid confusion)
noutram 0:5c5a623dc9e0 51 void printBinary12(unsigned short u16)
noutram 0:5c5a623dc9e0 52 {
noutram 0:5c5a623dc9e0 53 unsigned int mask = 0x800; //Binary 1000000000000000
noutram 0:5c5a623dc9e0 54 for (unsigned int n=0; n<12; n++) {
noutram 0:5c5a623dc9e0 55 //Test to see if the bit is set
noutram 0:5c5a623dc9e0 56 if (u16 & mask) {
noutram 0:5c5a623dc9e0 57 pc.printf("1");
noutram 0:5c5a623dc9e0 58 } else {
noutram 0:5c5a623dc9e0 59 pc.printf("0");
noutram 0:5c5a623dc9e0 60 }
noutram 0:5c5a623dc9e0 61 //Shift mask 1 bit right
noutram 0:5c5a623dc9e0 62 mask >>= 1;
noutram 0:5c5a623dc9e0 63 }
noutram 0:5c5a623dc9e0 64 pc.printf("\n");
noutram 0:5c5a623dc9e0 65 }