AT89LV55-12AC Atmel, AT89LV55-12AC Datasheet - Page 4

• Manufacturer Part Number: AT89LV55-12AC
• Description: IC 8051 MCU FLASH 20K 44TQFP
• Manufacturer: Atmel
• Series: 89LVr

Specifications of AT89LV55-12AC

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: UART/USART
• Number Of I /o: 32
• Program Memory Size: 20KB (20K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-TQFP, 44-VQFP
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: UART
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3 bit
• Operating Supply Voltage: 2.7 V to 6 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -
• Peripherals: -
• Lead Free Status / Rohs Status: No

4. Pin Description
4.1
4.2
4.3
4.4
4.5
4
V
GND
Port 0
Port 1
Port 2
AT89LV55
CC
Supply voltage.
Ground.
Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink eight TTL
inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs.
Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses
to external program and data memory. In this mode, P0 has internal pullups.
Port 0 also receives the code bytes during Flash programming and outputs the code bytes dur-
ing program verification. External pullups are required during program verification.
Port 1 is an 8-bit bi-directional I/O port with internal pullups. The Port 1 output buffers can
sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the inter-
nal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low
will source current (I
In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input
(P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the follow-
ing table.
Port 1 also receives the low-order address bytes during Flash programming and verification.
Port 2 is an 8-bit bi-directional I/O port with internal pullups. The Port 2 output buffers can
sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the inter-
nal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low
will source current (I
Port 2 emits the high-order address byte during fetches from external program memory and dur-
ing accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this
application, Port 2 uses strong internal pullups when emitting 1s. During accesses to external
data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special
Function Register.
Port 2 also receives the high-order address bits and some control signals during Flash program-
ming and verification.
Port Pin
P1.0
P1.1
Alternate Functions
T2 (external count input to Timer/Counter 2), clock-out
T2EX (Timer/Counter 2 capture/reload trigger and direction control)
IL
IL
) because of the internal pullups.
) because of the internal pullups.
0811E–MICRO–9/08