32

AT89S8252

0401F–MICRO–11/03

AC Characteristics

Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN = 100 pF; load capacitance for all other

outputs = 80 pF.

External Program and Data Memory Characteristics

Symbol

Parameter

Variable Oscillator

Units

Min

Max

1/t

CLCL

Oscillator Frequency

0

24

MHz

ALE Pulse Width

ns

t

AVLL

Address Valid to ALE Low

t

ns

t

LLAX

Address Hold after ALE Low

t

ns

ALE Low to Valid Instruction In

ns

t

LLPL

ALE Low to PSEN Low

t

ns

t

PLPH

PSEN Pulse Width

3t

ns

PSEN Low to Valid Instruction In

ns

t

PXIX

Input Instruction Hold after PSEN

0ns

t

PXIZ

Input Instruction Float after PSEN

t

ns

PSEN to Address Valid

ns

t

AVIV

Address to Valid Instruction In

5t

ns

t

PLAZ

PSEN Low to Address Float

10

ns

RD Pulse Width

ns

t

WLWH

WR Pulse Width

6t

ns

t

RLDV

RD Low to Valid Data In

5t

ns

Data Hold after RD

0ns

t

RHDZ

Data Float after RD

2t

ns

t

LLDV

ALE Low to Valid Data In

8t

ns

Address to Valid Data In

ns

t

LLWL

ALE Low to RD or WR Low

3t

3t

ns

t

AVWL

Address to RD or WR Low

4t

ns

Data Valid to WR Transition

ns

t

QVWH

Data Valid to WR High

7t

ns

t

WHQX

Data Hold after WR

t

ns

RD Low to Address Float

0

ns

t

WHLH

RD or WR High to ALE High

t

t

ns