PURPOSE: To decrease the number of parts and also to reduce power consumption by using a ROM reading control circuit to control the reading of the contents of plural ROMs and multiplexing the output of those ROMs to separate them again into signals corresponding to those ROMs.
CONSTITUTION: A ROM reading control circuit 11 controls the reading of ROMs 12, 13... and m-bit information read out of (n) pieces of ROM is multiplexed by a multiplexing circuit 16. Thus (m×n) multiplex information is obtained. This multiplex information is separated into the original m-fold multiplex signals again by a separating circuit 17. Thus it is not required to use the multiplexing circuits for each ROM. This can decrease the number of parts and also reduce the power consumption of a memory reading circuit.