int count=0;
char coord[4] = {'\0', '\0', '\0', '\0',};
int t_i = 0;
void TIM3_IRQHandler() {
    char key = key_scan();
    char input;
    if (phase == 0) {
    	char result = getchar_irq();

    	if (my_turn == 'Y') {
    		if (key != '\0') {
    			t_i++;
    			putchar_irq(key);
    			if (t_i == 4) {
        			pb8out();
        			putchar_irq('Y');
    				my_turn = 'N';
    			}
    			t_i = t_i % 4;
    		}
    	}
    	else if (my_turn == 'N') {
    		if ((result - 48 >= 0) && (result - 48 <= 9)) {
    			coord[t_i] = result;
    			t_i = (t_i + 1) % 4;
    			if (t_i == 0) {
    				my_turn = 'Y';
    			}
    		}
    	}
    }