Table 29. Overriding Signals for Alternate Functions in PA3..PA0
Signal
Name
PUOE
PUOV
PA3/AD3
PA2/AD2
PA1/AD1
PA0/AD0
SRE
SRE
SRE
SRE
~(WR | ADA) •
PORTA3 • PUD
~(WR | ADA) •
PORTA2 • PUD
~(WR | ADA) •
PORTA1 • PUD
~(WR | ADA) •
PORTA0 • PUD
DDOE
DDOV
PVOE
PVOV
SRE
SRE
SRE
SRE
WR | ADA
SRE
WR | ADA
SRE
WR | ADA
SRE
WR | ADA
SRE
A3 • ADA | D3
OUTPUT • WR
A2• ADA | D2
OUTPUT • WR
A1 • ADA | D1
OUTPUT • WR
A0 • ADA | D0
OUTPUT • WR
DIEOE
DIEOV
DI
0
0
0
0
0
0
0
0
D3 INPUT
–
D2 INPUT
–
D1 INPUT
–
D0 INPUT
–
AIO
Alternate Functions of The Port B pins with alternate functions are shown in Table 30.
Port B
Table 30. Port B Pins Alternate Functions
Port Pin Alternate Functions
OC2/OC1C(1) (Output Compare and PWM Output for Timer/Counter2 or Output
Compare and PWM Output C for Timer/Counter1)
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
OC1B (Output Compare and PWM Output B for Timer/Counter1)
OC1A (Output Compare and PWM Output A for Timer/Counter1)
OC0 (Output Compare and PWM Output for Timer/Counter0)
MISO (SPI Bus Master Input/Slave Output)
MOSI (SPI Bus Master Output/Slave Input)
SCK (SPI Bus Serial Clock)
SS (SPI Slave Select input)
Note:
1. OC1C not applicable in ATmega103 compatibility mode.
The alternate pin configuration is as follows:
• OC2/OC1C, Bit 7
OC2, Output Compare Match output: The PB7 pin can serve as an external output for the
Timer/Counter2 Output Compare. The pin has to be configured as an output (DDB7 set “one”) to
serve this function. The OC2 pin is also the output pin for the PWM mode timer function.
OC1C, Output Compare Match C output: The PB7 pin can serve as an external output for the
Timer/Counter1 Output Compare C. The pin has to be configured as an output (DDB7 set (one))
to serve this function. The OC1C pin is also the output pin for the PWM mode timer function.
74
ATmega128(L)
2467P–AVR–08/07
ATMEL [ ATMEL ]
