| 摘要 |
PURPOSE:To ensure coping with a same circuit configuration despite the change of a memory map by setting a memory map after decoding a specific bit of an address signal via an ROM with the written memory map. CONSTITUTION:An access is given to an ROM4 where a memory map is written and set by the selection provided by a map mode selection switch 7 and specific bits A0, A14, A15, etc. of addresses A0-A15, etc. given from a CPU via a bus driver 1. Then map setting information S1-S3 are delivered together with write and read control commands R and W via a decoding circuit 8. The bus drivers 5 and 6 corresponding to an RAM2 and an ROM3 formed on the same substrate respectively are activated in response to the information S1-S3 to set a memory map. Thus it is possible to ensure the same coping with the same circuit configuration with no change of a pattern despite the change of the memory map. This improves the productivity of memory circuits. |
