ATmega16(L)
• SDA – Port C, Bit 1
SDA, Two-wire Serial Interface Data: When the TWEN bit in TWCR is set (one) to enable the
Two-wire Serial Interface, pin PC1 is disconnected from the port and becomes the Serial Data
I/O pin for the Two-wire Serial Interface. In this mode, there is a spike filter on the pin to sup-
press spikes shorter than 50 ns on the input signal, and the pin is driven by an open drain driver
with slew-rate limitation. When this pin is used by the Two-wire Serial Interface, the pull-up can
still be controlled by the PORTC1 bit.
• SCL – Port C, Bit 0
SCL, Two-wire Serial Interface Clock: When the TWEN bit in TWCR is set (one) to enable the
Two-wire Serial Interface, pin PC0 is disconnected from the port and becomes the Serial Clock
I/O pin for the Two-wire Serial Interface. In this mode, there is a spike filter on the pin to sup-
press spikes shorter than 50 ns on the input signal, and the pin is driven by an open drain driver
with slew-rate limitation. When this pin is used by the Two-wire Serial Interface, the pull-up can
still be controlled by the PORTC0 bit.
and
relate the alternate functions of Port C to the overriding signals shown in
Table 29.
Overriding Signals for Alternate Functions in PC7..PC4
Signal
Name
PUOE
PUOV
DDOE
DDOV
PVOE
PVOV
DIEOE
DIEOV
DI
AIO
PC7/TOSC2
AS2
0
AS2
0
0
0
AS2
0
–
T/C2 OSC OUTPUT
PC6/TOSC1
AS2
0
AS2
0
0
0
AS2
0
–
T/C2 OSC INPUT
PC5/TDI
JTAGEN
1
JTAGEN
0
0
0
JTAGEN
0
–
TDI
PC4/TDO
JTAGEN
0
JTAGEN
SHIFT_IR
+
SHIFT_DR
JTAGEN
TDO
JTAGEN
0
–
–
62
2466S–AVR–05/09
ATMEL [ ATMEL CORPORATION ]
