main.cpp

00001 #include "mbed.h"
00002 Serial pc(USBTX, USBRX); // comms to host PC
00003 BusOut Seg1(p5,p6,p7,p8,p9,p10,p11,p12); // A,B,C,D,E,F,G,DP
00004 BusOut Seg2(p13,p14,p15,p16,p17,p18,p19,p20); // A,B,C,D,E,F,G,DP
00005 void SegInit(void); // function prototype
00006 void HostInit(void); // function prototype
00007 char GetKeyInput(void); // function prototype
00008 char SegConvert(char SegValue); // function prototype
00009 char data1, data2; // variable declarations
00010 int main()   // main program
00011 {
00012     SegInit(); // call function to initialise the 7-seg displays
00013     HostInit(); // call function to initialise the host terminal
00014     while (1) { // infinite loop
00015         data2 = GetKeyInput(); // call function to get 1st key press
00016         Seg2=SegConvert(data2); // call function to convert and output
00017         data1 = GetKeyInput(); // call function to get 2nd key press
00018         Seg1=SegConvert(data1); // call function to convert and output
00019         pc.printf(" "); // display spaces between 2 digit numbers
00020     }
00021 }
00022 
00023 void SegInit(void)
00024 {
00025     Seg1=SegConvert(0); // initialise to zero
00026     Seg2=SegConvert(0); // initialise to zero
00027 }
00028 void HostInit(void)
00029 {
00030     pc.printf("\n\rType two digit numbers to be displayed on the 7-seg display\n\r");
00031 }
00032 char GetKeyInput(void)
00033 {
00034     char c = pc.getc(); // get keyboard data (note num. ascii range 0x30-0x39)
00035     pc.printf("%c",c); // print ascii value to host PC terminal
00036     return (c&0x0F); // return value as non-ascii (bitmask c with value 0x0F)
00037 }
00038 
00039 char SegConvert(char SegValue)   // function 'SegConvert'
00040 {
00041     char SegByte=0x00;
00042     switch (SegValue) { //DPGFEDCBA
00043         case 0 :
00044             SegByte = 0x3F;
00045             break; // 00111111 binary
00046         case 1 :
00047             SegByte = 0x06;
00048             break; // 00000110 binary
00049         case 2 :
00050             SegByte = 0x5B;
00051             break; // 01011011 binary
00052         case 3 :
00053             SegByte = 0x4F;
00054             break; // 01001111 binary
00055         case 4 :
00056             SegByte = 0x66;
00057             break; // 01100110 binary
00058         case 5 :
00059             SegByte = 0x6D;
00060             break; // 01101101 binary
00061         case 6 :
00062             SegByte = 0x7D;
00063             break; // 01111101 binary
00064         case 7 :
00065             SegByte = 0x07;
00066             break; // 00000111 binary
00067         case 8 :
00068             SegByte = 0x7F;
00069             break; // 01111111 binary
00070         case 9 :
00071             SegByte = 0x6F;
00072             break; // 01101111 binary
00073     }
00074     return SegByte;
00075 }