
54
1477K–AVR–08/10
ATtiny26(L)
DI/SDA/OC1A/PCINT0 – Port B, Bit 0
DI: Data Input in USI Three-wire mode. USI Three-wire mode does not override normal port
functions., so pin must be configure as an input.
SDA: Serial Data in USI Two-wire mode. Serial data pin is bi-directional and uses open-collector
output. The SDA pin is enabled by setting the pin as an output. The pin is pulled low when the
PORTB0 or USI shiftRegister is zero when DDB0 is set (one). Pull-up is disabled in USI Two-
wire mode.
OC1A: Inverted Timer/Counter1 PWM output A: The PB0 pin can serve as an Inverted output for
the PWM mode if not used in programming or USI. The PB0 pin has to be configured as an out-
put (DDB0 set (one)) to serve this function.
PCINT0: Pin Change Interrupt 0 pin. Pin change interrupt is enabled on pin when global interrupt
is enabled, pin change interrupt is enabled and the alternate functions do not mask the interrupt.
The masking alternate functions are the inverted output compare match output OC1A and USI
data DI or SDA. Digital input is enabled on pin PB0 also in SLEEP modes, if the pin change
interrupt is enabled and not masked by the alternate functions.
Table 27 and
Table 28 relate the
2. Note that the PCINT1 Interrupt is only enabled if both the Global Interrupt Flag is enabled, the PCIE1 flag in GIMSK is set
4. External low level interrupt is enabled if both the Global Interrupt Flag is enabled and the INT0 flag in GIMSK is set as
5. Not operator is marked with “~”.
Table 27. Overriding Signals for Alternate Functions in PB7..PB4
Signal
Name
PB7/ADC10/RESET/
PCINT1
PB6/ADC9/INT0/TO/
PCINT1
PB5/ADC8/XTAL2/
PCINT1
PB4/ADC7/XTAL1
PUOE
PUOV
1
0
DDOE
0
DDOV
0
PVOE
0
PVOV
0
DIEOE
DIEOV
1
EXT_CLOCK_ENABLE
DI
PCINT1
INT0, T0, PCINT1
PCINT1
External Clock, PCINT1
AIO
ADC10, RESET INPUT
ADC9
ADC8, XTAL2
XTAL1