Semiconductor integrated circuit device with built-in memories.

摘要

A data processing LSI constructing a microcomputer has an EPROM (2) for changing a program. The EPROM can be accessed directly through the external terminals of the data processing LSI. The EPROM is statically operated when it is written with data by direct access. However, the statically operated EPROM consumes relatively high power. This power consumption by the EPROM is reduced by dynamically operating its read circuit (25), address decoder (22) and so on. For example, the read circuit is constructed of a sense amplifier (SA) and a latch circuit (34), and the sense amplifier (SA) has its operation interrupted after the latch circuit (34) has latched the read data. The address decoder (22) is composed of a load MOSFET (Qp) and address MOSFETs (Qd). The load MOSFET is caused to act as a precharge element in the dynamic operation and as an operation current feeding element in the static operation.