User Manual

103
T89C51AC2
Rev. B – 19-Dec-01
18.4.8 Shift Register Timing
Waveform s
18.4.9 External Clock Dri ve
Characteristics (XTAL1)
Table 68. AC Parameters
18.4.10 External Cl ock Drive
Waveform s
18.4.11 AC Testing
Input/Output Waveforms
AC inputs during testing are driven at V
CC
- 0. 5 for a logic “1” and 0.45V for a l ogic “0”.
Timing meas urement are made at V
IH
min for a logic “1” and V
IL
max for a l ogic “0”.
VALID VALID VALID VALID
VALIDVALID
INPUT DATA
VALID
0123456 87
ALE
CLOCK
OUTPUT DATA
WRITE to SBUF
CLEAR RI
T
XLXL
T
QVXH
T
XHQX
T
XHDV
T
XHDX
SET TI
SET RI
INSTRUCTION
01234567
VALID
Symbol Parameter Min Max Units
T
CLCL
Oscillator Period 25 ns
T
CHCX
High Time 5 ns
T
CLCX
Low Time 5 ns
T
CLCH
Rise Time 5 ns
T
CHCL
Fall Time 5 ns
T
CHCX
/T
CLCX
CyclicratioinX2mode 40 60 %
V
CC
-0.5V
0.45V
0.7V
CC
0.2V
CC
-0.1
T
CHCL
T
CLCX
T
CLCL
T
CLCH
T
CHCX
INPUT/OUTPUT
0.2 V
CC
+0.9
0.2 V
CC
-0.1
V
CC
-0.5 V
0.45 V