Rainbow Electronics AT89C55WD - Manual (Page 31)

31
AT89C55WD
1921B–MICRO–09/02
External Data Memory Write Cycle
External Clock Drive Waveforms
t
LHLL
t
LLWL
t
LLAX
t
WHLH
t
AVLL
t
WLWH
t
AVWL
t
QVWX
t
QVWH
t
WHQX
A0 - A7 FROM RI OR DPL
ALE
PSEN
WR
PORT 0
PORT 2 P2.0 - P2.7 OR A8 - A15 FROM DPH
A0 - A7 FROM PCL
A8 - A15 FROM PCH
DATA OUT INSTR IN
t
CHCX
t
CHCX
t
CLCX
t
CLCL
t
CHCL
t
CLCH
V - 0.5V
CC
0.45V
0.2 V - 0.1V
CC
0.7 V
CC
External Clock Drive
Symbol Parameter Min Max Units
1/t
CLCL
Oscillator Frequency 0 33 MHz
t
CLCL
Clock Period 30 ns
t
CHCX
High Time 12 ns
t
CLCX
Low Time 12 ns
t
CLCH
Rise Time 5 ns
t
CHCL
Fall Time 5 ns