Datasheet

78
7799D–AVR–11/10
ATmega8U2/16U2/32U2
Reset, Reset input. External Reset input is active low and enabled by unprogramming ("1") the
RSTDISBL Fuse. Pullup is activated and output driver and digital input are deactivated when the
pin is used as the RESET pin.
dW, debugWire channel. When the debugWIRE Enable (DWEN) Fuse is programmed and Lock
bits are unprogrammed, the debugWIRE system within the target device is activated. The
RESET port pin is configured as a wired -AND (open-drain) bi-directional I/O pin with pull-up
enabled and becomes the communication gateway between the target and the emulator.
•
XTAL2, Bit 0
XTAL2, Oscillator. The PC0 pin can serve as Inverting Output for internal Oscillator amplifier.
Table 12-7 and Table 12-8 relate the alternate functions of Port C to the overriding signals
shown in Figure 12-5 on page 72.
Table 12-7. Overriding Signals for Alternate Functions in PC7..PC4
Signal
Name PC7/ICP1/INT4/CLK0
PC6/PCINT8/
OC1A
PC5/PCINT9/
OC1B PC4/PCINT10
PUOE 0 0 0 0
PUOV 0 0 0 0
DDOE 0 0 0 0
DDOV 0 0 0 0
PVOE 0 OC1A ENABLE OC1B ENABLE 0
PVOV 0 OC1A OC1B 0
DIEOE INT4 ENABLE PCINT8 ENABLE PCINT9 ENABLE PCINT10 ENABLE
DIEOV 1 1 1 1
DI INT4 INPUT PCINT8 INPUT PCINT9 INPUT PCINT10 INPUT
AIO – – – –
Table 12-8. Overriding Signals for Alternate Functions in PC2..PC0
Signal
Name PC2/PCINT11 PC1/
RESET/dW PC0/XTAL2
PUOE 0 0 0
PUOV 0 0 0
DDOE 0 0 0
DDOV 0 0 0
PVOE 0 0 0
PVOV 0 0 0
DIEOE PCINT11 ENABLE 0 0
DIEOV 1 0 0
DI PCINT11 INPUT – –
AIO – – –