PROM BUILT-IN INTEGRATED CIRCUIT

摘要

PURPOSE:To prevent data written in a built-in PROM section from being read to an external device with a PROM writer and to keep the secrecy by providing a function reading the data written in the built-in PROM section and verifying the data to the circuit. CONSTITUTION:A write control section 1 receives write information by a control signal CNT to generate a write system. An address register 2 uses an address control signal ADC from the control section 1 to keep and output the address signal AD from a PROM writer 20. The built-in PROM section 3 according to a PROM control signal PCN from the control section 1 writes a write data DTW from the PROM writer 20 to an address designated by the signal AD. The PROM section 3 reads out the written data. A comparison section 4 according to a comparison control signal CCN compares the readout data DTR and DTW and outputs a coincidence confirming signal CMR. The PROM writer 20 decides whether or not the data DW is finished and the write to the PROM section 3 is finished when the data is finished.