T89C51RD2-SMFC-M View Datasheet(PDF) - Atmel Corporation
Part Name
Description
Manufacturer
T89C51RD2-SMFC-M Datasheet PDF : 86 Pages
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T89C51RD2
Mnemonic
VSS
Vss1
VCC
P0.0-P0.7
P1.0-P1.7
P2.0-P2.7
P3.0-P3.7
Pin Number
DIL LCC VQFP 1.4
20 22
16
1
39
40 44
38
39-32 43-36 37-30
1-8 2-9
40-44
1-3
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
21-28 24-31
40
41
42
43
44
1
2
3
18-25
10-17 11,
5,
13-19
7-13
10 11
5
11 13
7
12 14
8
13 15
9
14 16
10
15 17
11
16 18
12
Type
Name and Function
I Ground: 0V reference
I Optional Ground: Contact the Sales Office for ground connection.
I
Power Supply: This is the power supply voltage for normal, idle and power-
down operation
I/O Port 0: Port 0 is an open-drain, bidirectional I/O port. Port 0 pins that have 1s
written to them float and can be used as high impedance inputs. Port 0 must be
polarized to VCC or VSS in order to prevent any parasitic current consumption.
Port 0 is also the multiplexed low-order address and data bus during access to
external program and data memory. In this application, it uses strong internal
pull-up when emitting 1s. Port 0 also inputs the code bytes during EPROM
programming. External pull-ups are required during program verification during
which P0 outputs the code bytes.
I/O Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. Port 1 pins
that have 1s written to them are pulled high by the internal pull-ups and can be
used as inputs. As inputs, Port 1 pins that are externally pulled low will source
current because of the internal pull-ups. Port 1 also receives the low-order address
byte during memory programming and verification.
Alternate functions for TSC8x54/58 Port 1 include:
I/O T2 (P1.0): Timer/Counter 2 external count input/Clockout
I T2EX (P1.1): Timer/Counter 2 Reload/Capture/Direction Control
I ECI (P1.2): External Clock for the PCA
I/O CEX0 (P1.3): Capture/Compare External I/O for PCA module 0
I/O CEX1 (P1.4): Capture/Compare External I/O for PCA module 1
I/O CEX2 (P1.5): Capture/Compare External I/O for PCA module 2
I/O CEX3 (P1.6): Capture/Compare External I/O for PCA module 3
I/O CEX4 (P1.7): Capture/Compare External I/O for PCA module 4
I/O Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. 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 pulled low will
source current because of the internal pull-ups. Port 2 emits the high-order address
byte during fetches from external program memory and during accesses to external
data memory that use 16-bit addresses (MOVX @DPTR).In this application, it
uses strong internal pull-ups emitting 1s. During accesses to external data memory
that use 8-bit addresses (MOVX @Ri), port 2 emits the contents of the P2 SFR.
Some Port 2 pins receive the high order address bits during EPROM programming
and verification:
P2.0 to P2.5 for RB devices
P2.0 to P2.6 for RC devices
P2.0 to P2.7 for RD devices.
I/O 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 3 also serves the special features
of the 80C51 family, as listed below.
I RXD (P3.0): Serial input port
O TXD (P3.1): Serial output port
I INT0 (P3.2): External interrupt 0
I INT1 (P3.3): External interrupt 1
I T0 (P3.4): Timer 0 external input
I T1 (P3.5): Timer 1 external input
O WR (P3.6): External data memory write strobe
Rev. F - 15 February, 2001
7
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