1. Example 10 ASCII String to Binary Conversion
Lecture L4.3

2. ASCII number string to binary conversion
34671 = 3 x x x x
= (7 + 10(6 + 10(4 + 10(3))))

3. Algorithms to convert a double number to an ASCII string

4. char* ptr; // pointer to keypad buffer
char kbuf[12]; // keypad buffer
ptr = kbuf; // point to keypad buffer

5. Example 10
// Example 10: Calculator with ASCII string to number conversion
#include <hidef.h> /* common defines and macros */
#include <mc9s12dp256.h> /* derivative information */
#include "main_asm.h" /* interface to the assembly module */
#pragma LINK_INFO DERIVATIVE "mc9s12dp256b"
void main(void) {
long op1, op2; // 32-bit operands
char* ptr; // pointer to keypad buffer
char* plus; // string pointers
char* equals;
char* blanks;
char kbuf[12]; // keypad buffer
ptr = kbuf;
plus = "+ ";
equals = "= ";
blanks = " ";
char c, a;
int i;

6. Example 10 (cont.) // Example 10: (cont.)
PLL_init(); // set system clock frequency to 24 MHz
lcd_init(); // enable lcd
keypad_enable(); // enable keypad
set_lcd_addr(0x00); // display on 1st line
i = 0; // kbuf index = 0
while(1) {
c = getkey(); // read keypad
a = hex2asc(c); // convert to ascii
kbuf[i] = a; // and store in kbuf
if(c < 10){ // if 0 - 9
data8(a); // display on LCD
wait_keyup(); // wait to release key
i++; // inc index
} else {
switch(c){

7. Example 10 (cont.) // Example 10: (cont.)
case 0xE: // if enter (*) key
op1 = number(ptr); // convert to binary
set_lcd_addr(0x42); // display on 2nd line
write_long_lcd(op1);
set_lcd_addr(0x00); // clear 1st line
type_lcd(blanks);
wait_keyup(); // wait to release key
i = 0; // reset kbuf index
set_lcd_addr(0x00); // display on 1st line
break;

8. Example 10 (cont.) // Example 10: (cont.) case 0xA: // if key A
set_lcd_addr(0x42); // display op1 on 2nd line
write_long_lcd(op1);
op2 = number(ptr); // convert to binary
set_lcd_addr(0x14); // display on 3rd line
type_lcd(plus);
write_long_lcd(op2);
op1 = op1 + op2; // compute sum
set_lcd_addr(0x54); // display on 4th line
type_lcd(equals);
set_lcd_addr(0x00); // clear 1st line
type_lcd(blanks);
wait_keyup(); // wait to release key
i = 0; // reset kbuf index
set_lcd_addr(0x00); // display on 1st line
break;

9. Example 10 (cont.) // Example 10: (cont.)
case 0xF: // if clear (#) key
clear_lcd(); // clear lcd display
wait_keyup(); // wait to release key
i = 0; // reset kbuf index
break;
default: }