ATTINY9_14 Datasheet, PDF (45/170 Pages) ATMEL Corporation – Atmel 8-bit AVR Microcontroller

10.2.7 Program Example
The following code example shows how to set port B pin 0 high, pin 1 low, and define the port pins from 2 to 3 as
input with a pull-up assigned to port pin 2. The resulting pin values are read back again, but as previously dis-
cussed, a nop instruction is included to be able to read back the value recently assigned to some of the pins.
Assembly Code Example
...
; Define pull-ups and set outputs high
; Define directions for port pins
ldi r16,(1<<PUEB2)
ldi r17,(1<<PB0)
ldi r18,(1<<DDB1)|(1<<DDB0)
out PUEB,r16
out PORTB,r17
out DDRB,r18
; Insert nop for synchronization
nop
; Read port pins
in r16,PINB
...
Note: See “Code Examples” on page 5.
10.3
Alternate Port Functions
Most port pins have alternate functions in addition to being general digital I/Os. In Figure 10-6 below is shown how
the port pin control signals from the simplified Figure 10-2 on page 41 can be overridden by alternate functions.
ATtiny4/5/9/10 [DATASHEET] 45
8127F–AVR–02/2013