Question

char readKey() { char ch do { PORTA = OxOF; //set PA7-PA4 to 0 while (PORTA OXOF) { //keep checking PORTA until a key is pressed code = PORTA 1/get keycode delayms (10): //debounce from pressing key } } while(code != PORTA) { //check if PORTA changed code = readKeyCode (): //determine code of key pressed PORTA = OxOF //set P47-PA4 to 0 } while (PORTA != 0x0F) { //wait for release of key delayms (10): //debounce from release of key } ch = translate (code): //translate keycode to ascii return(ch): } ROW1 %1110 1111: ROW2 = %1101 1111; ROW3 %1011 1111: ROW4 %0111 1111:

translate this pseudocode to assmbler

Answer 1

char;
readKey();
{char;
ch;
for (
; // TODO: Warning!!!! NULL EXPRESSION DETECTED...
;
) {
    PORTA = 0;
    x0F;
    (PA7 - PA4);
    0;
    while () {
        0;
        x0F;
        key;
        checking;
        PORTA;
        a;
        (key == pressed);
        keycode;
        delayms(10);
        debounce;
        from;
        pressing;
        key;
        while (code) {
            PORTA;
            check;
            if (PORTA) {
                changed;
                code = readKeyCode();
                determine;
                code;
                of;
                key;
                pressed;
                PORTA = 0;
                (PA7 - PA4);
                0;
                while (PORTA) {
                    0;
                    x0F;
                    wait;
                    for (release; ; release++) {
                        of;
                        key;
                        delayms(10);
                        debounce;
                        from;
                        release;
                        of;
                        key;
                        ch = translate(code);
                        translate;
                        keycode;
                        ascii;
                        return ch;
                        1110;
                        1111;
                        1101;
                        1111;
                        1011;
                        1111;
                        111;
                        1111;
                    }
                    
                }
                
            }
            
        }
        
    }
    
}

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