IC80C51
IC80C31
ALE
t
WHLH
PSEN
WR
t
LLWL
tWLWH
t
AVLL
t
WHQX
t
QVWX
DATA OUT
t
LLAX
PORT 0
PORT 2
A7-A0 FROM RI OR DPL
A7-A0 FROM PCL
INSTR IN
t
AVWL
A15-A8 FROM DPH
Figure 30. External Data Memory Write Cycle
A15-A8 FROM PCH
INSTRUCTION
0
1
2
3
4
5
6
7
8
ALE
t
XLXL
CLOCK
DATAOUT
DATAIN
t
XHQX
t
QVXH
0
1
2
3
4
5
6
7
t
XHDX
SET TI
t
XHDV
VALID
VALID
VALID
VALID
VALID
VALID
VALID
VALID
SET RI
Figure 31. Shift Register Mode Timing Waveform
t
CLCX
tCHCX
Vcc — 0.5V
0.45V
0.7Vcc
0.2Vcc — 0.1
t
CHCL
tCLCH
t
CLCL
Figure 32. External Clock Drive Waveform
S3-42
Integrated Circuit Solution Inc.
MC001-0B