JPS6465633A - Microprogram controller - Google Patents

Abstract

PURPOSE:To easily rewrite and replace the contents of a ROM IC at the time of changing a microprogram and to improve echonomical efficiency by providing the titled device with a main storage part, an auxiliary storage part, a microprogram setting means, and an auxiliary storage writing means. CONSTITUTION:When a power supply is turned on, a control memory data setting circuit 5 is driven and a microprogram is read out from a ROM IC in a main storage part 6 and set up in a control memory 2. A memory is set up in a storage part 6, and at the time of turning on the power supply, data are not read out from an auxiliary storage part 7 and operation is started similarly to the ordinary case. Then, the initial program load is executed from the storage part 6 and changing data in the storage part 7 are also set up. On the other hand, microprogram changing information is read out from the storage part 7 on the basis of a micro-initializing signal generated at the time of loading. The initial reading data indicate start, the succeeding data indicate the writing of a microinstruction 1 in an address ADR1 of the memory 2 and the writing is started. Thus, the memory 2 is corrected until the detection of an end, and at the time of detecting the end, operation using the memory 2 can be restarted.