W78LE812

- 18 -

Data Read Cycle

PARAMETER

SYMBOL

MIN.

TYP.

MAX.

UNIT

NOTES

ALE Low to RD Low

∆

-

∆

nS

1, 2

RD Low to Data Valid

-

-

nS

1

Data Hold from RD High

0

-

nS

Data Float from RD High

0

-

nS

RD Pulse Width

∆

-

nS

2

Notes:

2. "

∆" (due to buffer driving delay and wire loading) is 20 nS.

Data Write Cycle

PARAMETER

SYMBOL

MIN.

TYP.

MAX.

UNIT

ALE Low to WR Low

∆

-

∆

nS

Data Valid to WR Low

∆

-

-

nS

Data Hold from WR High

∆

-

-

nS

WR Pulse Width

∆

-

nS

Note: "

∆" (due to buffer driving delay and wire loading) is 20 nS.

Port Access Cycle

PARAMETER

SYMBOL

MIN.

TYP.

MAX.

UNIT

Port Input Setup to ALE Low

-

-

nS

Port Input Hold from ALE Low

0

-

-

nS

Port Output to ALE

-

-

nS

Note: Ports are read during S5P2, and output data becomes available at the end of S6P2. The timing data are referenced to

ALE, since it provides a convenient reference.