p87c51mc2ba/02 NXP Semiconductors, p87c51mc2ba/02 Datasheet - Page 8

• Manufacturer Part Number: p87c51mc2ba/02
• Description: 80c51 8-bit Microcontroller Family With Extended Memory
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 2:
9397 750 12302
Product data
Symbol
P2.0 - P2.7
P3.0 - P3.7
P4.0 - P4.1
Pin description
Pin
24 - 31
11,13 -19
11
13
14
15
16
17
18
19
12,34
12
…continued
Type
I/O
I/O
I
O
I
I
I
I
O
O
I/O
I
I/O
Description
Port 2: Port 2 is a 8-bit bidirectional I/O port with internal pull-ups on all pins.
Port 2 pins that have 1s written to them are pulled HIGH by the internal pull-ups
and can be used as inputs. As inputs, port 2 pins that are externally being pulled
LOW will source current because of the internal pull-ups. (See
“Static
fetches from external program memory and during accesses to external data
memory that use 16-bit addresses (MOVX @ DPTR) or 23-bit addresses
(MOVX @EPTR, EMOV). In this application, it uses strong internal pull-ups
when emitting 1s. During accesses to external data memory that use 8-bit
addresses (MOV @ Ri), port 2 emits the contents of the P2 Special Function
Register.
Note that when 23-bit address is used, address bits A16-A22 will be outputted
to P2.0-P2.6 when ALE is HIGH, and address bits A8-A14 are outputted to
P2.0-P2.6 when ALE is LOW. Address bit A15 is outputted on P2.7 regardless
of ALE.
Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. Port 3 pins
that have 1s written to them are pulled HIGH by the internal pull-ups and can be
used as inputs. As inputs, port 3 pins that are externally pulled LOW will source
current because of the internal pull-ups.
Port 4: Port 4 is an 2-bit bidirectional I/O port with internal pull-ups on all pins.
Port 4 pins that have 1s written to them are pulled HIGH by the internal pull-ups
and can be used as inputs. As inputs, port 4 pins that are externally pulled LOW
will source current because of the internal pull-ups. As inputs, port 4 pins that
are externally pulled LOW will source current because of the internal pull-ups.
(Note: When SPEN, i.e.,SPCTL.6, is ’1’, the pull-ups at these port pins are
disabled.)
•
•
•
•
•
•
•
•
•
•
P3.0, RXD0
P3.1, TXD0
P3.2, INT0
P3.3, INT1
P3.4, T0
P3.5, T1
P3.6, WR
P3.7, RD
P4.0, RXD1
MISO
– Serial input port 0
– Serial output port 0
– External interrupt 0
– External interrupt 1
– Timer0 external input
– Timer1 external input
– External data memory write strobe
– External data memory read strobe
– Serial input port 1 (with pull-up on pin)
– SPI Master In/Slave Out (Selected when SFR bit SPEN (SPCTL.6) is ‘1’,
Rev. 03 — 13 November 2003
in which case the pull-up for this pin is disabled)
characteristics”, I
P87C51MB2/P87C51MC2
IL
). Port 2 emits the high-order address byte during
80C51 8-bit microcontroller family
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
Section 10
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