Bank-selecting Roms

摘要

Suppose the marketing department asks you to addrnsome new features to an existing product that uses an eight-bit 8085 or Z80 microprocessor as a dedicatedrncontroller. How can you upgrade the product withrnminimal changes to the hardware?rnIn many cases, the performance of an eight-bit, CPU-based dedicated controller can be increased simply by expanding the program. Larger programs can often perform more complex tasks and execute data-processing tasks faster. If memory space is available, the product can probably be upgraded with little or no change to the hardware. For example, controllers using standard cards often have a vacant ROM socket or one that can be jumpered for a larger ROM. In these cases, you're home free-aside, of course, from the minor technical details of creating the new software.