| 摘要 |
This invention proposes the ROM memory extension system which consists of a CPU and ROM devices. Before, to make use of memory map between CPU and ROM, it was common to sequentially use address area from the byte at the first address (OH). And to parallely connect a few ROMS, ROM address partially or entirely allocates. Thus, real system RAM and EEPROM spaces shorten the fixed ROM area. ROM memory extension system includes the BANK transfer function which is connected to 1st and 2nd high addresses input through address extension circuit. These circuits have exclusive-OR and inverter and AND, OR gates.
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