SEMICONDUCTOR CIRCUIT DEVICE

摘要

PURPOSE:To prevent processing content data written in a programmable ROM from being read by the third person and to hold the secrecy of system specification. CONSTITUTION:Based on read inhibit data '0' stored in a read inhibit information area 16 allocated into a PROM 3, an AND circuit 18a regulates the output of the processing content data from a PROM 3 to a general-purpose PROM data input/output circuit 7, and an AND circuit 18b regulates the output of test mode signals due to a CPU 1 for selectively outputting the processing content data, which are inputted from the PROM 3 to the CPU 1, to the outside.