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83C552 Datasheet, PDF (16/24 Pages) NXP Semiconductors – Single-chip 8-bit microcontroller
Philips Semiconductors
Single-chip 8-bit microcontroller
Product specification
80C552/83C552
EXPLANATION OF THE AC SYMBOLS
Each timing symbol has five characters. The Q – Output data
first character is always ‘t’ (= time). The other R – RD signal
characters, depending on their positions,
t – Time
indicate the name of a signal or the logical
V – Valid
status of that signal. The designations are:
W – WR signal
A – Address
X – No longer a valid logic level
C – Clock
Z – Float
D – Input data
H – Logic level high
Examples: tAVLL = Time for address valid to
ALE low.
I – Instruction (program memory contents)
L – Logic level low, or ALE
tLLPL = Time for ALE low to
PSEN low.
P – PSEN
ALE
PSEN
PORT 0
PORT 2
tLHLL
tAVLL
tLLPL
tLLIV
tPLPH
tPLIV
tLLAX
tPLAZ
tPXIX
tPXIZ
A0–A7
INSTR IN
tAVIV
A8–A15
A0–A7
A8–A15
Figure 2. External Program Memory Read Cycle
ALE
PSEN
RD
PORT 0
PORT 2
tWHLH
tLLDV
tLLWL
tRLRH
tAVLL
tLLAX
A0–A7
FROM RI OR DPL
tRLAZ
tRLDV
tRHDX
DATA IN
tAVWL
tAVDV
P2.0–P2.7 OR A8–A15 FROM DPH
tRHDZ
A0–A7 FROM PCL
A8–A15 FROM PCH
1998 Aug 13
Figure 3. External Data Memory Read Cycle
16
INSTR IN