Datasheet
Philips Semiconductors Product specification
8XC54/58
8XC51FA/FB/FC/80C51FA
8XC51RA+/RB+/RC+/RD+/80C51RA+
80C51 8-bit microcontroller family
8K–64K/256–1K OTP/ROM/ROMless, low voltage (2.7V–5.5V),
low power, high speed (33MHz)
2000 Aug 07
41
t
LLAX
ALE
PSEN
PORT 0
PORT 2
WR
A0–A7
FROM RI OR DPL
DATA OUT A0–A7 FROM PCL INSTR IN
P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH
t
WHLH
t
LLWL
t
WLWH
t
AVLL
t
AVWL
t
QVWX
t
WHQX
t
QVWH
SU00026
Figure 31. External Data Memory Write Cycle
012345678
INSTRUCTION
ALE
CLOCK
OUTPUT DATA
WRITE TO SBUF
INPUT DATA
CLEAR RI
VALID VALID VALID VALID VALID VALID VALID VALID
SET TI
SET RI
t
XLXL
t
QVXH
t
XHQX
t
XHDX
t
XHDV
SU00027
1230 4567
Figure 32. Shift Register Mode Timing
V
CC
–0.5
0.45V
0.7V
CC
0.2V
CC
–0.1
t
CHCL
t
CLCL
t
CLCH
t
CLCX
t
CHCX
SU00009
Figure 33. External Clock Drive