ACK:        SETB SDA
BACK:       SETB SCK
            JB SDA,LEDX     ;if SDA is high then go to LEDX LABEL
EXIT:       CLR SCK         ;if SDA is low then clear the SCK
            RET	            ;Go back
LEDX:       CLR LED         ;Clear the LED pin for tracking
            SJMP BACK       ;Go back to BACK and check it again