Chapter 13 local bus interface function – NEC PD78214 User Manual
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CHAPTER 13 LOCAL BUS INTERFACE FUNCTION
The local bus interface function is provided to connect external memories (ROM and RAM) and I/Os.
External memories (ROM and RAM) and I/Os are accessed by using the RD, WR, and ASTB signals, a multiplexed
address/data bus consisting of lines AD0 to AD7, and an address bus consisting of lines A8 to A19. Figs. 13-3 and
13-4 show the basic bus interface timing diagrams.
In addition, a wait function for interfacing with low-speed memory, and a refresh signal output function for
refreshing pseudo static RAM, are provided.