UPD784907 Datasheet, PDF (59/98 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784907, 784908
10. LOCAL BUS INTERFACE
The local bus interface enables the connection of external memory and I/O devices (memory mapped I/O) and
supports a 1-Mbyte memory space (see Figure 10-1).
Figure 10-1. Example of Local Bus Interface
µPD784908
A16 to A19
RD
WR
REFRQ
Pseudo SRAM
PROM
µ PD27C1001A
Kanji character
generator
µPD24C1000
AD0 to AD7
Data bus
ASTB
A8 to A15
Latch
Address bus
Gate array for I/O
expansion including
Centronics interface
circuit, etc.
10.1 Memory Expansion
By adding external memory, program memory or data memory can be expanded, 256 bytes at a time, to
approximately 1 Mbyte (seven steps).
Data Sheet U11680EJ2V0DS00
59