AT89C51IC2 Atmel Corporation, AT89C51IC2 Datasheet - Page 12

• Manufacturer Part Number: AT89C51IC2
• Manufacturer: Atmel Corporation

Specifications of AT89C51IC2

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

Table 13. Pin Description for 40/44 Pin Packages (Continued)
12
XTALA1
XTALA2
XTALB1
XTALB2
P2.0 - P2.7
P3.0 - P3.7
PI2.0 - PI2.1
Mnemonic
AT89C51IC2
PLCC44
24 - 31
13 - 19
34, 12
11,
21
20
13
14
15
16
17
18
19
34
12
11
9
2
1
Pin Number
VQFP44 1.4
18 - 25
7 - 13
28, 6
15
14
40
39
10
11
12
13
28
5,
3
5
7
8
9
6
Type
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
O
O
O
I
I
I
I
I
I
I
Name and Function
P1.7: Input/Output:
CEX4: Capture/Compare External I/O for PCA module 4
MOSI: SPI Master Output Slave Input line
When SPI is in master mode, MOSI outputs data to the slave peripheral. When SPI is
in slave mode, MOSI receives data from the master controller.
Crystal A 1: Input to the inverting oscillator amplifier and input to the internal clock
generator circuits.
Crystal A 2: Output from the inverting oscillator amplifier
Crystal B 1: (Sub Clock) Input to the inverting oscillator amplifier and input to the inter-
nal clock generator circuits.
Crystal B 2: (Sub Clock) Output from the inverting oscillator amplifier
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.
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.
RXD (P3.0): Serial input port
TXD (P3.1): Serial output port
INT0 (P3.2): External interrupt 0
INT1 (P3.3): External interrupt 1
T0 (P3.4): Timer 0 external input
T1 (P3.5): Timer 1 external input
WR (P3.6): External data memory write strobe
RD (P3.7): External data memory read strobe
Port I2: Port I2 is an open drain. It can be used as inputs (must be polarized to Vcc
with external resistor to prevent any parasitic current consumption).
SCL (PI2.0): 2-wire Serial Clock
SCL output the serial clock to slave peripherals
SCL input the serial clock from master
SDA (PI2.1): 2-wire Serial Data
4301D–8051–02/08