AT80C51RD2 Atmel Corporation, AT80C51RD2 Datasheet - Page 4

• Manufacturer Part Number: AT80C51RD2
• Manufacturer: Atmel Corporation

Specifications of AT80C51RD2

• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 1.25
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Watchdog: Yes

Table 3-1.
4
Mnemonic
V
V
P0.0 - P0.7
P1.0 - P1.7
XTAL1
XTAL2
SS
CC
AT80C51RD2
Pin Description
39 - 32
1 - 8
DIL
20
40
19
18
1
2
3
4
5
6
7
8
PLCC44
43 - 36
Pin Number
2 - 9
22
44
21
20
2
3
4
5
6
7
8
9
VQFP44 1.4
37 - 30
40 - 44
1 - 3
16
38
40
41
42
43
44
15
14
1
2
3
Type
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
I
I
I
I
I
Name and Function
Ground: 0V reference
Power Supply: This is the power supply voltage for normal, idle and power-down
operation
Port 0: Port 0 is an open-drain, bi-directional 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 V
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.
Port 1: Port 1 is an 8-bit bi-directional 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 T89C51RB2/RC2 Port 1 include:
P1.0: Input/Output
T2 (P1.0): Timer/Counter 2 external count input/Clockout
P1.1: Input/Output
T2EX: Timer/Counter 2 Reload/Capture/Direction Control
P1.2: Input/Output
ECI: External Clock for the PCA
P1.3: Input/Output
CEX0: Capture/Compare External I/O for PCA module 0
P1.4: Input/Output
CEX1: Capture/Compare External I/O for PCA module 1
P1.5: Input/Output
CEX2: Capture/Compare External I/O for PCA module 2
P1.6: Input/Output
CEX3: Capture/Compare External I/O for PCA module 3
P1.7: Input/Output:
CEX4: Capture/Compare External I/O for PCA module 4
Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock
generator circuits.
Crystal 2: Output from the inverting oscillator amplifier
CC
or V
SS
in order to prevent any parasitic current consumption. Port
4113D–8051–01/09