Chapter 13 local bus interface function – NEC PD78214 User Manual
Page 378
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Chapter 13 Local Bus Interface Function
13
Fig. 13-5 Accessing Expansion Data Memory
(a) Read cycle
RD (output)
A16-A19
(output)
Contents of P6/PM6 register
Higher address
Higher address
Lower
address
(output)
Hi-Z
Hi-Z
Program
(input)
Lower
address
(output)
Data
(input)
Hi-Z
Hi-Z
Hi-Z
A8-A15
(output)
AD0-AD7
ASTB (output)
Fetch cycle
Expansion data memory access cycle
(b) Write cycle
RD (output)
A16-A19
(output)
Contents of P6/PM6 register
Higher address
Higher address
Lower
address
(output)
Hi-Z
Hi-Z
Program
(input)
Lower
address
(output)
Data (input)
Hi-Z
Hi-Z
A8-A15
(output)
AD0-AD7
ASTB (output)
Fetch cycle
Expansion data memory access cycle
WR (output)