p87c51mc2 NXP Semiconductors, p87c51mc2 Datasheet - Page 23

• Manufacturer Part Number: p87c51mc2
• Description: 80c51 8-bit Microcontroller Family With Extended Memory
• Manufacturer: NXP Semiconductors

EXPLANATION OF 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
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
2001 Apr 06
Philips Semiconductors
AVLL
LLPL
80C51 8-bit microcontroller family with extended memory
64KB/96KB OTP with 2KB/3KB RAM
- Time for ALE low to PSEN low
- Time for address valid to ALE low.
PORT 0
PORT 2
PSEN
ALE
Figure 1: External Program Memory Read Cycle (Non-Extended Memory Cycle)
t
LHLL
t
AVLL
t
LLAX
t
LLPL
A0-A7
t
PLAZ
t
AVIV
t
LLIV
t
PLIV
P2.0-P2.7 OR A8-A15
t
PLPH
23
INSTR IN
t
PXIX
P87C51MB2/P87C51MC2
t
PXIZ
A0-A7
Preliminary specification