P89V52X2 Datasheet, PDF (46/57 Pages) NXP Semiconductors – 8-bit 80C51 low power 8 kB flash microcontroller with 256 B RAM, 192 B data EEPROM

NXP Semiconductors
P89V52X2
80C51 with 256 B RAM, 192 B data EEPROM
9.1 Explanation of symbols
Each timing symbol has 5 characters. The first character is always a ‘t’ (stands for time).
The other characters, depending on their positions, stand for the name of a signal or the
logical status of that signal. The following is a list of all the characters and what they stand
for.
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 — High impedance (Float)
Example:
t_AVLL = Address valid to ALE LOW time
t_LLPL = ALE LOW to PSEN LOW time
ALE
PSEN
port 0
port 2
t_LHLL
t_AVLL
t_LLPL
t_LLIV
t_PLIV
t_PLPH
t_LLAX
A0 to A7
t_PLAZ
t_PXIZ
t_PXIX
INSTR IN
tAVIV
A8 to A15
Fig 21. External program memory read cycle
t_PXAV
A0 to A7
A8 to A15
002aaa548
P89V52X2_3
Product data sheet
Rev. 03 — 4 May 2009
© NXP B.V. 2009. All rights reserved.
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