S80C851-4N44 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

S80C851-4N44

CMOS single-chip 8-bit microcontroller with on-chip EEPROM

Philips Electronics 

Philips Semiconductors

CMOS single-chip 8-bit microcontroller

with on-chip EEPROM

Product specification

80C851/83C851

EXPLANATION OF THE

AC SYMBOLS

Each timing symbol has five characters. The

first character is always ‘t’ (= time). The other

characters, depending on their positions,

indicate the name of a signal or the logical

status of that signal. The designations are:

A – Address

C – Clock

D – Input data

H – Logic level high

I – Instruction (program memory contents)

L – Logic level low, or ALE

P – PSEN

Q – Output data

R – RD signal

t – Time

V – Valid

W – WR signal

X – No longer a valid logic level

Z – Float

Examples: tAVLL= Time for address valid to

ALE low.

tLLPL= Time for ALE low to

PSEN low.

ALE

PSEN

PORT 0

PORT 2

tLHLL

tAVLL tLLPL

tPLPH

tLLIV

tPLIV

tLLAX

tPLAZ

tPXIX

tPXIZ

A0–A7

INSTR IN

tAVIV

A8–A15

A0–A7

A8–A15

Figure 4. External Program Memory Read Cycle

ALE

PSEN

RD

PORT 0

PORT 2

1998 Jul 03

tLLDV

tLLWL

tRLRH

tWHLH

tAVLL

tLLAX

A0–A7

FROM RI OR DPL

tRLAZ

tRLDV

tRHDX

DATA IN

tAVWL

tAVDV

P2.0–P2.7 OR A8–A15 FROM DPH

tRHDZ

A0–A7 FROM PCL

A8–A15 FROM PCH

Figure 5. External Data Memory Read Cycle

14

INSTR IN

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