P87C660X2 PHILIPS [NXP Semiconductors], P87C660X2 Datasheet - Page 88

• Manufacturer Part Number: P87C660X2
• Description: 80C51 8-bit microcontroller family
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
EXPLANATION OF THE AC SYMBOLS
Each timing symbol has five characters. The first character is always
‘t’ (= time). The other characters, depending on their positions,
indicate the name of a signal or the logical status of that signal. The
designations are:
A – Address
C – Clock
D – Input data
H – Logic level HIGH
I – Instruction (program memory contents)
L – Logic level LOW, or ALE
2003 Oct 02
PORT 0
PORT 2
80C51 8-bit microcontroller family
RAM, low voltage (2.7 to 5.5 V), low power, high speed (30/33
MHz), two 400KB I
PSEN
ALE
RD
PORT 0
PORT 2
PSEN
ALE
t
AVLL
2
C interfaces
FROM RI OR DPL
A0–A7
t
LLAX
t
t
AVWL
LHLL
t
t
LLWL
AVLL
A0–A7
Figure 50. External Program Memory Read Cycle
16 KB OTP/ROM, 512B
t
t
AVDV
P2.0–P2.7 OR A8–A15 FROM DPF
RLAZ
Figure 51. External Data Memory Read Cycle
t
LLDV
t
t
t
AVIV
LLAX
LLPL
t
LLIV
t
t
PLIV
RLDV
A0–A15
t
PLAZ
t
PLPH
t
RLRH
t
PXIX
INSTR IN
88
t
RHDX
DATA IN
P – PSEN
Q – Output data
R – RD signal
t – Time
V – Valid
W – WR signal
X – No longer a valid logic level
Z – Float
Examples: t
t
PXIZ
t
RHDZ
t
t
AVLL
WHLH
LLPL
= Time for address valid to ALE LOW.
=Time for ALE LOW to PSEN LOW.
A0–A7
A0–A7 FROM PCL
A0–A15 FROM PCH
P8xC660X2/661X2
A8–A15
SU00006
INSTR IN
Product data
SU00025