AT90S4433 Datasheet, PDF (78/126 Pages) ATMEL Corporation – 8-Bit AVR Microcontroller with 4K Bytes of In-System Programmable Flash

Port C Data Register – PORTC
Bit
7
$15 ($35)
–
Read/Write
R
Initial Value
0
6
5
4
3
2
1
0
–
PORTC5 PORTC4 PORTC3 PORTC2 PORTC1 PORTC0 PORTC
R
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
Port C Data Direction Register
– DDRC
Bit
7
$14 ($34)
–
Read/Write
R
Initial Value
0
6
5
4
3
2
1
0
–
DDC5
DDC4
DDC3
DDC2
DDC1
DDC0
DDRC
R
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
Port C Input Pins Address –
PINC
Bit
7
$13 ($33)
–
Read/Write
R
Initial Value
0
6
5
4
3
2
1
0
–
PINC5 PINC4 PINC3 PINC2 PINC1 PINC0
PINC
R
R
R
R
R
R
R
0
N/A
N/A
N/A
N/A
N/A
N/A
The Port C Input Pins address (PINC) is not a register; this address enables access to
the physical value on each Port C pin. When reading PORTC, the Port C Data Latch is
read, and when reading PINC, the logical values present on the pins are read.
Port C as General Digital I/O
All six pins in Port C have equal functionality when used as digital I/O pins.
PCn, general I/O pin: The DDCn bit in the DDRC Register selects the direction of this
pin. If DDCn is set (one), PCn is configured as an output pin. If DDCn is cleared (zero),
PCn is configured as an input pin. If PORTCn is set (one) when the pin is configured as
an input pin, the MOS pull-up resistor is activated. To switch the pull-up resistor off,
PORTCn has to be cleared (zero) or the pin has to be configured as an output pin.The
port pins are tri-stated when a reset condition becomes active, even if the clock is not
running.
Table 25. DDCn Effects on Port C Pins⁽¹⁾
DDCn PORTCn
I/O
Pull-up Comment
0
0
Input
No
Tri-state (high-Z)
0
1
Input
Yes PCn will source current if ext. pulled low.
1
0
Output
No
Push-pull Zero Output
1
1
Output
Note: 1. n: 5..0, pin number
No
Push-pull One Output
78 AT90S/LS4433
1042H–AVR–04/03