File content as of revision 0:918d74953a0f:

// main program code for Exercise 7-6
#include "mbed.h"
Serial pc(USBTX, USBRX); // comms to host PC
BusOut Seg1(p5,p6,p7,p8,p9,p10,p11,p12); // A,B,C,D,E,F,G,DP
BusOut Seg2(p13,p14,p15,p16,p17,p18,p19,p20); // A,B,C,D,E,F,G,DP
void SegInit(void); // function prototype
void HostInit(void); // function prototype
char GetKeyInput(void); // function prototype
char SegConvert(char SegValue); // function prototype
char data1, data2; // variable declarations
int main()   // main program
{
    SegInit(); // call function to initialise the 7-seg displays
    HostInit(); // call function to initialise the host terminal
    while (1) { // infinite loop
        data2 = GetKeyInput(); // call function to get 1st key press
        Seg2=SegConvert(data2); // call function to convert and output
        data1 = GetKeyInput(); // call function to get 2nd key press
        Seg1=SegConvert(data1); // call function to convert and output
        pc.printf(" "); // display spaces between 2 digit numbers
    }
}
void SegInit(void)
{
    Seg1=SegConvert(0); // initialise to zero
    Seg2=SegConvert(0); // initialise to zero
}
void HostInit(void)
{
    pc.printf("\n\rType two digit numbers to be displayed on the 7-seg display\n\r");
}
char GetKeyInput(void)
{
    char c = pc.getc(); // get keyboard data (note num. ascii range 0x30-0x39)
    pc.printf("%c",c); // print ascii value to host PC terminal
    return (c&0x0F); // return value as non-ascii (bitmask c with value 0x0F)
}
char SegConvert(char SegValue)   // function 'SegConvert'
{
    char SegByte=0x00;
    switch (SegValue) { //DPGFEDCBA
        case 0 :
            SegByte = 0x3F;
            break; // 00111111 binary
        case 1 :
            SegByte = 0x06;
            break; // 00000110 binary
        case 2 :
            SegByte = 0x5B;
            break; // 01011011 binary
        case 3 :
            SegByte = 0x4F;
            break; // 01001111 binary
        case 4 :
            SegByte = 0x66;
            break; // 01100110 binary
        case 5 :
            SegByte = 0x6D;
            break; // 01101101 binary
        case 6 :
            SegByte = 0x7D;
            break; // 01111101 binary
        case 7 :
            SegByte = 0x07;
            break; // 00000111 binary
        case 8 :
            SegByte = 0x7F;
            break; // 01111111 binary
        case 9 :
            SegByte = 0x6F;
            break; // 01101111 binary
    }
    return SegByte;
}