ADDRESS CIRCUIT FOR IMAGE MEMORY

摘要

PURPOSE:To confirm the operation of a logical circuit without increasing the number of IC output terminals by using an external IC terminal to be a data output in normal memory operation as an address confirming terminal in the case of including the logical circuit in a memory. CONSTITUTION:In normal memory operation, an address selecting circuit 7 selects an address input terminal 6 and an inputted signal is entered into an address register 8 and led into an address decoder 13. A data selecting circuit 10 selects a reading means 5 and data read out from a memory cell 4 is led into an output terminal 2. When a test signal is turned to a low level, an address shifted by an address shifting circuit 9 is selected by the circuit 7 and inputted to the register 8. Thereby, one bit of the address is successively shifted and outputted from the terminal 2. Since the address stored in the same IC as the memory can be outputted from the terminal in the test mode, the operation of an address generating circuit can be easily confirmed.