Datasheet

93
2549O–AVR–05/12
ATmega640/1280/1281/2560/2561
• OC4B – Port H, Bit 4
OC4B, Output Compare Match B output: The PH4 pin can serve as an external output for the
Timer/Counter2 Output Compare B. The pin has to be configured as an output (DDH4 set) to
serve this function. The OC4B pin is also the output pin for the PWM mode timer function.
• OC4A – Port H, Bit 3
OC4C, Output Compare Match A output: The PH3 pin can serve as an external output for the
Timer/Counter4 Output Compare A. The pin has to be configured as an output (DDH3 set) to
serve this function. The OC4A pin is also the output pin for the PWM mode timer function.
• XCK2 – Port H, Bit 2
XCK2, USART2 External Clock: The Data Direction Register (DDH2) controls whether the clock
is output (DDH2 set) or input (DDH2 cleared). The XC2K pin is active only when the USART2
operates in synchronous mode.
• TXD2 – Port H, Bit 1
TXD2, USART2 Transmit Pin.
• RXD2 – Port H, Bit 0
RXD2, USART2 Receive pin: Receive Data (Data input pin for the USART2). When the
USART2 Receiver is enabled, this pin is configured as an input regardless of the value of DDH0.
When the USART2 forces this pin to be an input, a logical on in PORTH0 will turn on the internal
pull-up.
Table 13-25. Overriding Signals for Alternate Functions in PH7:PH4
Signal Name PH7/T4 PH6/OC2B PH5/OC4C PH4/OC4B
PUOE0 000
PUOV0 000
DDOE 0 0 0 0
DDOV0 000
PVOE 0 OC2B ENABLE OC4C ENABLE OC4B ENABLE
PVOV 0 OC2B OC4C OC4B
PTOE– –––
DIEOE0 000
DIEOV0 000
DI T4 INPUT000
AIO– –––