P89V51RD2 Philips Semiconductors, P89V51RD2 Datasheet - Page 9

• 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
Table 3:
[1]
[2]
9397 750 12964
Product data
Symbol
EA
ALE/
PROG
NC
XTAL1
XTAL2
V
V
DD
SS
ALE loading issue: When ALE pin experiences higher loading (>30 pF) during the reset, the microcontroller may accidentally enter into
modes other than normal working mode. The solution is to add a pull-up resistor of 3 k to 50 k to V
For 6-clock mode, ALE is emitted at
P89V51RD2 pin description
Pin
DIP40
31
30
-
19
18
40
20
TQFP44
29
27
6, 17, 28,
39
15
14
38
16
1
3
PLCC44
35
33
1, 12, 23,
34
21
20
44
22
of crystal frequency.
…continued
Rev. 01 — 01 March 2004
Type
I
I/O
I/O
I
O
I
I
Description
External Access Enable: EA must be connected to V
in order to enable the device to fetch code from the
external program memory. EA must be strapped to V
for internal program execution. However, Security lock
level 4 will disable EA, and program execution is only
possible from internal program memory. The EA pin can
tolerate a high voltage of 12 V.
Address Latch Enable: ALE is the output signal for
latching the low byte of the address during an access to
external memory. This pin is also the programming
pulse input (PROG) for flash programming. Normally the
ALE
frequency
clocking. One ALE pulse is skipped during each access
to external data memory. However, if AO is set to ‘1’,
ALE is disabled.
No Connect
Crystal 1: Input to the inverting oscillator amplifier and
input to the internal clock generator circuits.
Crystal 2: Output from the inverting oscillator amplifier.
Power supply
Ground
[1]
is emitted at a constant rate of
[2]
8-bit microcontrollers with 80C51 core
and can be used for external timing and
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
DD
P89V51RD2
, e.g., for ALE pin.
1
6
the crystal
9 of 75
DD
SS