atmega323l ATMEL Corporation, atmega323l Datasheet - Page 148

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Port C Schematics
148
ATmega323(L)
• TCK – Port C, Bit 2
TCK, JTAG Test Clock: JTAG operation is synchronous to TCK. When the JTAG inter-
face is enabled, this pin can not be used as an I/O pin. Refer to the section “JTAG
Interface and the On-chip Debug System” on page 157 for details on operation of the
JTAG interface.
• 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 capture spikes shorter than 50 ns on the input signal, and the
pin is driven by an open collector driver with slew rate limitation.
• 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 PC1 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 capture spikes shorter than 50 ns on the input signal.
Note that all port pins are synchronized. The synchronization latches are not shown in
the figure.
Figure 75. Port C Schematic Diagram (Pins PC0 - PC1)
PCn
PUD: PULL-UP DISABLE
n = 0, 1
PUD
0
1
0
1
0
DDCn
SCL/SDA out
SCL/SDA in
TWEN
n
1457G–AVR–09/03