HD6475328CG Datasheet, PDF (452/459 Pages) Hitachi Semiconductor – Manual Gives a Hardware Description

4. Mode 4
Figures E-7 and E-8 show how the pin states change when the RES pin goes Low during external
memory access in mode 4.
As soon as RES goes Low, all ports are initialized to the input (high-impedance) state. The AS,
DS, RD, and WR signals all go High. The data bus (D7 to D0) is placed in the high-impedance
state. Pins P57/A15 to P50/A8 of the address bus and pins P63/A19 to P60/A16 of the page address
bus are initialized as input ports.
Pins A7 to A0 of the address bus and the R/W signal are initialized 1.5 ø clock periods after the
Low state of the RES pin is sampled. Pins A7 to A0 are made Low. The R/W signal is made
High.
The clock output pins P10/ø and P11/E are initialized 0.5 ø clock periods after the Low state of the
RES pin is sampled. Both pins are initialized to the output state.
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