External program memory read cycle, External data memory read cycle, At89c55wd – Rainbow Electronics AT89C55WD User Manual

Page 30

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30

AT89C55WD

1921B–MICRO–09/02

External Program Memory Read Cycle

External Data Memory Read Cycle

t

LHLL

t

LLIV

t

PLIV

t

LLAX

t

PXIZ

t

PLPH

t

PLAZ

t

PXAV

t

AVLL

t

LLPL

t

AVIV

t

PXIX

ALE

PSEN

PORT 0

PORT 2

A8 - A15

A0 - A7

A0 - A7

A8 - A15

INSTR IN

t

LHLL

t

LLDV

t

LLWL

t

LLAX

t

WHLH

t

AVLL

t

RLRH

t

AVDV

t

AVWL

t

RLAZ

t

RHDX

t

RLDV

t

RHDZ

A0 - A7 FROM RI OR DPL

ALE

PSEN

RD

PORT 0

PORT 2

P2.0 - P2.7 OR A8 - A15 FROM DPH

A0 - A7 FROM PCL

A8 - A15 FROM PCH

DATA IN

INSTR IN

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