p89c538nbb NXP Semiconductors, p89c538nbb Datasheet - Page 18

• Manufacturer Part Number: p89c538nbb
• Description: Cmos Single-chip 8-bit Microcontrollers With Flash Program Memory
• Manufacturer: 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
1998 Apr 24
PORT 0
PORT 2
80C51 8-bit microcontroller family
16K/64K/512 FLASH
PSEN
ALE
RD
PORT 0
PORT 2
PSEN
ALE
t
AVLL
FROM RI OR DPL
A0–A7
t
LLAX
t
t
AVWL
LHLL
t
t
LLWL
AVLL
A0–A7
Figure 9.
t
t
AVDV
P2.0–P2.7 OR A8–A15 FROM DPF
Figure 10.
RLAZ
t
LLDV
t
t
t
AVIV
LLAX
LLPL
t
LLIV
External Program Memory Read Cycle
t
t
PLIV
RLDV
A0–A15
External Data Memory Read Cycle
t
PLAZ
t
PLPH
t
RLRH
t
PXIX
INSTR IN
18
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
WHLH
AVLL
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
A8–A15
89C536/89C538
Preliminary specification
SU00006
INSTR IN
SU00025