main.cpp

00001 #include "mbed.h"
00002 #include <map>
00003 
00004 //Initialize serial comms
00005 Serial pc(USBTX, USBRX);
00006 
00007 //Initialize PMW
00008 PwmOut PWM1(p21);
00009 
00010 
00011 //Initialize Keypad I/O
00012 DigitalOut row1(p26);
00013 DigitalOut row2(p23);
00014 DigitalOut row3(p24);
00015 DigitalOut row4(p25);
00016 
00017 DigitalIn col1(p20);
00018 DigitalIn col2(p19);
00019 DigitalIn col3(p18);
00020 DigitalIn col4(p17);
00021 Timer t1;
00022 
00023 //map used for keypad
00024 map<int, char> keypadMap;
00025 
00026 
00027 //Map for keypad
00028 //First 4 bits corrospond to active column
00029 //Last 4 bits corrospond to active row
00030 void init(){
00031         keypadMap[0x11]='1';
00032         keypadMap[0x12]='2';
00033         keypadMap[0x14]='3';
00034         keypadMap[0x18]='A';
00035         keypadMap[0x21]='4';
00036         keypadMap[0x22]='5';
00037         keypadMap[0x24]='6';
00038         keypadMap[0x28]='B';
00039         keypadMap[0x41]='7';
00040         keypadMap[0x42]='8';
00041         keypadMap[0x44]='9';
00042         keypadMap[0x48]='C';
00043         keypadMap[0x81]='*';
00044         keypadMap[0x82]='0';
00045         keypadMap[0x84]='#';
00046         keypadMap[0x88]='D';
00047 }
00048 
00049 int main() {
00050     init();
00051     //Initialize rows to 0
00052     row1 = 0;
00053     row2 = 0;
00054     row3 = 0;
00055     row4 = 0;
00056     t1.start();
00057     int input = 0x00;
00058     while(1) {
00059         //make all rows 0 to add stability
00060         row1 = 0;
00061         row2 = 0;
00062         row3 = 0;
00063         row4 = 0;
00064        //Keep each led lit for 4ms
00065        switch(t1.read_ms()%4){
00066                         case 0: row1 = 1;
00067                                 input |= 0x10;   
00068                                 break;
00069                         case 1: row2 = 1;
00070                                 input |= 0x20;
00071                                 break;
00072                         case 2: row3 = 1;
00073                                 input |= 0x40;
00074                                 break;
00075                         case 3: row4 = 1; 
00076                                 input |= 0x80;
00077                                 break; }
00078          //Pull the value from each column and check to see if 1
00079          if(col1 == 1)
00080             input |= 0x01;
00081          else if(col2 == 1)
00082             input |= 0x02;
00083          else if(col3 == 1)
00084             input |= 0x04;
00085          else if(col4 == 1)
00086             input |= 0x08;
00087          
00088          char c = keypadMap[input]; //assign charcter based on input
00089          //Print to the terminal the character if available 
00090          if(c != 0){
00091             pc.printf("%c\r",c);  //print input and char
00092          }
00093          //reset input
00094          input = 0x00;     
00095     }
00096 }