ATmega162 datasheet(67/324 Pages) ATMEL

67 / 324 page

2513K–AVR–07/09

ATmega162/V

The following code example shows how to set port B pins 0 and 1 high, 2 and 3 low, and define

the port pins from 4 to 7 as input with pull-ups assigned to port pins 6 and 7. 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:

1. For the assembly program, two temporary registers are used to minimize the time from pull-

ups are set on pins 0, 1, 6, and 7, until the direction bits are correctly set, defining bit 2 and 3

as low and redefining bits 0 and 1 as strong high drivers.

Digital Input Enable

and Sleep Modes

As shown in Figure 29, the digital input signal can be clamped to ground at the 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, Standby mode, and Extended Standby mode to avoid

high power consumption if some input signals are left floating, or have an analog signal level

close to V

CC/2.

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 “Alternate Port Functions” on page 68.

If a logic high level (“one”) is present on an Asynchronous External Interrupt pin configured as

“Interrupt on Rising Edge, Falling Edge, or Any Logic Change on Pin” while the external interrupt

is not enabled, the corresponding External Interrupt Flag will be set when resuming from the

above mentioned sleep modes, as the clamping in these sleep modes produces the requested

logic change.

Assembly Code Example(1)

...

; Define pull-ups a?d set outputs high

; Define directions?for port pins

ldi

r16,(1<<PB7)|(1<<PB6)|(1<<PB1)|(1<<PB0)

ldi

r17,(1<<DDB3)|(1<<DDB2)|(1<<DDB1)|(1<<DDB0)

out

PORTB,r16

out

DDRB,r17

; Insert nop for sy?chronization

nop

; Read port pins

r16,PINB

...

C Code Example(1)

unsigned char

...

/* Define pull-ups ?nd set outputs high */

/* Define direction? for port pins */

PORTB = (1<<PB7)|(1<<PB6?|(1<<PB1)|(1<<PB0);

DDRB = (1<<DDB3)|(1<<DDB?)|(1<<DDB1)|(1<<DDB0);

/* Insert nop for s?nchronization*/

_NOP();

/* Read port pins */

i = PINB;

...

ATmega162 Datasheet(PDF) 67 Page - ATMEL Corporation

ATmega162 Datasheet(HTML) 67 Page - ATMEL Corporation

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