| 摘要 |
PROBLEM TO BE SOLVED: To access an external memory having various memory characteristics by making good use of only microcodes. SOLUTION: A memory type program block 22 outputs a value stored in an internal register with an offset value, add value, in response to a sequence field signal from a microcode ROM 12. A microcode program counter 20 receives the offset value, add value, and increases a program counter value by the offset value add value, and outputs a next microcode address corresponding to the increased program counter value. The microcode ROM 12 stores a microcode used to access the external memory. The memory type program block 22 stores the characteristic value of the external memory that a user has programmed, in response to an ALE program register enable signal and a wait program register enable signal.
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