7.5.2 Check Lock Command

The Check Lock command follows the same sequence as the Lock command (including 0110b in the A7 through A4 bits of the memory address byte) with the exception that only the device address byte and memory address byte need to be transmitted to the device. An ACK response to the memory address byte indicates that the lock has not been set while a NACK response indicates that the lock has been set. If the lock has already been enabled, it cannot be reversed. The Check Lock command is completed when the host sends a Stop bit to the device (defined as a null bit frame).