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Implementing Mixed Memory Modes on the eZ80 CPU

Implementing Mixed Memory Modes on the eZ80 CPU

This application note describes the two types of memory modes offered by the eZ80 CPU and provides a simple application to demonstrate how to properly configure the eZ80 CPU for a mixed memory mode of operation. As a result, you will be able to run blocks of legacy Z80 code from within the eZ80 CPU environment.


The eZ80 CPU offers two types of memory modes: Z80 Mode and Address Data Long (ADL) Mode. Z80 Mode offers backward compatibility with legacy Z80 applications, while ADL Mode offers 24-bit linear addressing and 24-bit CPU registers. These multiple memory modes of the eZ80 processor allow developers to easily migrate older Z80 or Z180 codes to the new ADL Mode codes.