ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 60

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

12.2.5
60
Atmel ATtiny24/44/84 [Preliminary]
Digital Input Enable and Sleep Modes
The following code example shows how to set port A pins 0 and 1 high, 2 and 3 low, and
define the port pins from 4 to 5 as input with a pull-up assigned to port pin 4. The resulting pin
values are read back again, but as previously discussed, a nop instruction is included to be
able to read back the value recently assigned to some of the pins.
Note:
As shown in
input of the schmitt-trigger. The signal denoted SLEEP in the figure, is set by the MCU Sleep
Controller in Power-down mode, Power-save mode, and Standby mode to avoid high power
consumption if some input signals are left floating, or have an analog signal level close to
V
SLEEP is overridden for port pins enabled as external interrupt pins. If the external interrupt
request is not enabled, SLEEP is active also for these pins. SLEEP is also overridden by vari-
ous other alternate functions as described in
Assembly Code Example
C Code Example
CC
/2.
unsigned char i;
...
; Define pull-ups and set outputs high
; Define directions for port pins
ldi
ldi
out
out
; Insert nop for synchronization
nop
; Read port pins
in
...
...
/* Define pull-ups and set outputs high */
/* Define directions for port pins */
PORTA = (1<<PA4)|(1<<PA1)|(1<<PA0);
DDRA = (1<<DDA3)|(1<<DDA2)|(1<<DDA1)|(1<<DDA0);
/* Insert nop for synchronization*/
_NOP();
/* Read port pins */
i = PINA;
...
1. For the assembly program, two temporary registers are used to minimize the time from
pull-ups are set on pins 0, 1 and 4, until the direction bits are correctly set, defining bit 2 and
3 as low and redefining bits 0 and 1 as strong high drivers.
Figure 12-2 on page
r16,(1<<PA4)|(1<<PA1)|(1<<PA0)
r17,(1<<DDA3)|(1<<DDA2)|(1<<DDA1)|(1<<DDA0)
PORTA,r16
DDRA,r17
r16,PINA
(1)
57, the digital input signal can be clamped to ground at the
“Alternate Port Functions” on page
7701E–AVR–02/11
61.