PURPOSE: To write data in a desired PROM through the use of one master ROM by providing a selecting means to supply selectively write-in information from a PROM writer to the desired PROM.
CONSTITUTION: An adapter 6 for PROM writer is provided with a built-in decoder 8. The decoder 8 decodes a part of address data, supplied form an EPROM 5, and generates select signals CE2WCE4 for controlling selectively the prescribed EPROM among the EPROMs 2W4 into an operatable state. Then, when all the write-in data is supplied to a writer 5 one time from the master ROM 7, and write-in is started, the decoder 8 controls selectively the prescribed EPROMs 2W4 into the operatable state according to the address data. Thus, the data can be written in plural EPROMs 2W4, contained in a microcomputer chip 1, by using one master ROM 7.
MATSUO AKINORI
WATANABE MASARU
FUJIMOTO MICHIO
NAGAYAMA YOSHIHARU
HITACHI VLSI ENG