| 摘要 |
PURPOSE:To omit the operation of a scan address supply, to dispense even with an I/F signal for the address supply and to make a device into a simple constitution by automatically patrolling and preparing a scan ring address with an address counter without giving it from an external part. CONSTITUTION:An address decoder 5 to decode the address of the scan ring and an address counter 6 to hold the address and to designate the address in executing an ascending order or a descending order are provided, and a scan-in/out is controlled by a time division. Since the scan-in/out is controlled by the time division by designating the scan address with the address counter 6 in executing the ascending order or descending order, the operation to give the scan address from the external part can be made unnecessary, and a scan address signal line can be made also unnecessary. Thus, the constitution can be made simple and inexpensive. |
