Philips Semiconductors Product data
P89C60X2/61X2
80C51 8-bit Flash microcontroller family
64KB Flash, 512B/1024B RAM
2003 Sep 11
49
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
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
AVLL
= Time for address valid to ALE low.
t
LLPL
=Time for ALE low to PSEN low.
t
PXIZ
ALE
PSEN
PORT 0
PORT 2
A0–A15 A8–A15
A0–A7 A0–A7
t
AVLL
t
PXIX
t
LLAX
INSTR IN
t
LHLL
t
PLPH
t
LLIV
t
PLAZ
t
LLPL
t
AVIV
SU00006
t
PLIV
Figure 31. External Program Memory Read Cycle
ALE
PSEN
PORT 0
PORT 2
RD
A0–A7
FROM RI OR DPL
DATA IN A0–A7 FROM PCL INSTR IN
P2.0–P2.7 OR A8–A15 FROM DPF A0–A15 FROM PCH
t
WHLH
t
LLDV
t
LLWL
t
RLRH
t
LLAX
t
RLAZ
t
AVLL
t
RHDX
t
RHDZ
t
AVWL
t
AVDV
t
RLDV
SU00025
Figure 32. External Data Memory Read Cycle
