AT89C51IC2-RLTIM ATMEL [ATMEL Corporation], AT89C51IC2-RLTIM Datasheet - Page 11

• Manufacturer Part Number: AT89C51IC2-RLTIM
• Description: 8-bit Flash Microcontroller with 2-wire Interface
• Manufacturer: ATMEL [ATMEL Corporation]

Table 13. Pin Description for 40/44 Pin Packages
4301C–8051–06/06
V
V
P0.0 - P0.7
P1.0 - P1.7
SS
CC
Mnemonic
PLCC44
43 - 36
2 - 9
22
44
2
3
4
5
6
7
8
Pin Number
VQFP44 1.4
37 - 30
40 - 44
1 - 3
16
38
40
41
42
43
44
1
2
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
I
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, 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 V
or V
plexed 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 dur-
ing program verification during which P0 outputs the code bytes.
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 AT89C51IC2 Port 1 include:
P1.0: Input/Output
T2 (P1.0): Timer/Counter 2 external count input/Clockout
XTALB1 (P1.0): Sub Clock input to the inverting oscillator amplifier
P1.1: Input/Output
T2EX: Timer/Counter 2 Reload/Capture/Direction Control
SS: SPI Slave Select
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
MISO: SPI Master Input Slave Output line
When SPI is in master mode, MISO receives data from the slave peripheral. When SPI
is in slave mode, MISO outputs data to the master controller.
P1.6: Input/Output
CEX3: Capture/Compare External I/O for PCA module 3
SCK: SPI Serial Clock
SCK outputs clock to the slave peripheral
SS
in order to prevent any parasitic current consumption. Port 0 is also the multi-
AT89C51IC2
CC
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