| 摘要 |
<p>PURPOSE:To early detect a fault by counting the number of received data invalid codes when a synchronizing fault occurs at the received data and shifting automatically the operation to a synchronization detecting mode when the counted number of invalid codes exceeds a fixed level. CONSTITUTION:When a synchronizing fault occurs at the received data and a reception circuit (a) becomes idle, the invalid codes are written into a reception buffer 3 in a synchronous circuit 2. Then a comparator 5 detects continuously the invalid codes and the value (n) of a counter 7 increases. When a comparator 8 decides the coincidence between the prescribed invalid code continuous reception allowing frequency (p) and the counter value (n), an invalid code reception interruption signal (s) is outputted to an external circuit. The counter 7 is cleared by the signal (s) and a synchronization detecting instruction signal (d) is inputted to the circuit 2 from the external circuit. Then the operation is shifted to a synchronization detecting mode.</p> |
