Rainbow Electronics ATmega8515L - Manual (Page 69)

69
ATmega8515(L)
2512A–AVR–04/02
Alternate Functions of Port D The Port D pins with alternate functions are shown in Table 35.
The alternate pin configuration is as follows:
• RD – Port D, Bit 7
RD is the External Data memory read control strobe.
• WR – Port D, Bit 6
WR is the External Data memory write control strobe.
• OC1A – Port D, Bit 5
OC1A, Output Compare Match A output: The PD5 pin can serve as an external output
for the Timer/Counter1 Output Compare A. The pin has to be configured as an output
(DDD5 set (one)) to serve this function. The OC1A pin is also the output pin for the
PWM mode timer function.
• XCK – Port D, Bit 4
XCK, USART External Clock. The Data Direction Register (DDD4) controls whether the
clock is output (DDD4 set) or input (DDD4 cleared). The XCK pin is active only when
USART operates in Synchronous mode.
• INT1 – Port D, Bit 3
INT1, External Interrupt source 1: The PD3 pin can serve as an external interrupt
source.
• INT0/XCK1 – Port D, Bit 2
INT0, External Interrupt Source 0: The PD2 pin can serve as an external interrupt
source.
XCK1, External Clock. The Data Direction Register (DDD2) controls whether the clock is
output (DDD2 set) or input (DDD2 cleared).
• TXD – Port D, Bit 1
TXD, Transmit Data (Data output pin for USART). When the USART Transmitter is
enabled, this pin is configured as an output regardless of the value of DDD1.
Table 35. Port D Pins Alternate Functions
Port Pin Alternate Function
PD7 RD (Read Strobe to External Memory)
PD6 WR (Write Strobe to External Memory)
PD5 OC1A (Timer/Counter1 Output Compare A Match Output)
PD4 XCK (USART External Clock Input/Output)
PD3 INT1 (External Interrupt 1 Input)
PD2 INT0 (External Interrupt 0 Input)
PD1 TXD (USART Output Pin)
PD0 RXD (USART Input Pin)