AT89C2051-12SU Atmel, AT89C2051-12SU Datasheet - Page 3

• Manufacturer Part Number: AT89C2051-12SU
• Description: IC 8051 MCU FLASH 2K 20SOIC
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C2051-12SU

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: UART/USART
• Peripherals: LED
• Number Of I /o: 15
• Program Memory Size: 2KB (2K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SOIC (7.5mm Width)
• Package: 20SOIC
• Device Core: 8051
• Family Name: 89C
• Maximum Speed: 12 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 15
• Interface Type: UART
• Number Of Timers: 2
• Processor Series: AT89x
• Core: 8051
• Data Ram Size: 128 B
• Maximum Clock Frequency: 12 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4. Pin Description
4.1
4.2
4.3
4.4
4.5
4.6
0368H–MICRO–6/08
VCC
GND
Port 1
Port 3
RST
XTAL1
Supply voltage.
Ground.
The Port 1 is an 8-bit bi-directional I/O port. Port pins P1.2 to P1.7 provide internal pull-ups. P1.0
and P1.1 require external pull-ups. P1.0 and P1.1 also serve as the positive input (AIN0) and the
negative input (AIN1), respectively, of the on-chip precision analog comparator. The Port 1 out-
put buffers can sink 20 mA and can drive LED displays directly. When 1s are written to Port 1
pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally
pulled low, they will source current (I
Port 1 also receives code data during Flash programming and verification.
Port 3 pins P3.0 to P3.5, P3.7 are seven bi-directional I/O pins with internal pull-ups. P3.6 is
hard-wired as an input to the output of the on-chip comparator and is not accessible as a gen-
eral-purpose I/O pin. The Port 3 output buffers can sink 20 mA. When 1s are written to Port 3
pins they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3
pins that are externally being pulled low will source current (I
Port 3 also serves the functions of various special features of the AT89C2051 as listed below:
Port 3 also receives some control signals for Flash programming and verification.
Reset input. All I/O pins are reset to 1s as soon as RST goes high. Holding the RST pin high for
two machine cycles while the oscillator is running resets the device.
Each machine cycle takes 12 oscillator or clock cycles.
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
Port Pin
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
Alternate Functions
RXD (serial input port)
TXD (serial output port)
INT0 (external interrupt 0)
INT1 (external interrupt 1)
T0 (timer 0 external input)
T1 (timer 1 external input)
IL
) because of the internal pull-ups.
IL
) because of the pull-ups.
AT89C2051
3