P89V51RD2 Philips Semiconductors, P89V51RD2 Datasheet - Page 65

• Manufacturer Part Number: P89V51RD2
• Description: 8-bit 80C51 5 V low power 64 kB Flash microcontroller with 1 kB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 12964
Product data
Fig 30. External program memory read cycle.
PORT 0
PORT 2
PSEN
ALE
11.1 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
T
t AVLL
AVLL
LLPL
t LHLL
= Time from ALE LOW to PSEN LOW
= Time from Address Valid to ALE LOW
t LLAX
A0 - A7
t LLPL
Rev. 01 — 01 March 2004
t AVIV
A8 - A15
t PLAZ
t PLIV
t LLIV
t PXIX
INSTR IN
t PXIZ
8-bit microcontrollers with 80C51 core
t PLPH
t PXAV
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
A0 - A7
A8 - A15
P89V51RD2
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