p89cv51rb2 NXP Semiconductors, p89cv51rb2 Datasheet - Page 60

• Manufacturer Part Number: p89cv51rb2
• Description: P89cv51rb2/rc2/rd2 8-bit 80c51 5 V Low Power 64 Kb Flash Microcontroller With 1 Kb Ram, Spi, 6-clock Cpu With 6/12-clock Peripherals
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89CV51RB2_RC2_RD2_1
Product data sheet
Fig 29. External program memory read cycle
PSEN
port 0
port 2
ALE
9.1 Explanation of symbols
Each timing symbol used in
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 — cycle Time
V — Valid
W — WR signal
X — No longer a valid logic level
Z — High impedance (float)
Example:
t
t
AVLL
LLPL
t
= Address valid to ALE LOW time
= ALE LOW to PSEN LOW time
AVLL
t
LHLL
t
LLAX
A0 to A7
t
LLPL
t AVIV
Rev. 01 — 5 October 2007
Figure 29
A8 to A15
t
PLAZ
t
t
to
PLIV
LLIV
INSTR IN
t
P89CV51RB2/RC2/RD2
PXIX
Figure 33
t
PXIZ
t
PLPH
has 5 characters. The first character is
t
PXAV
A0 to A7
A8 to A15
80C51 with 1 kB RAM, SPI
002aaa548
© NXP B.V. 2007. All rights reserved.
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