Rainbow-electronics ATmega128L Uživatelský manuál stáhnout pdf (Strana 65)

ATmega128(L)

2467B–09/01

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

/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 various other alternate functions as described in

“Alternate Port Func-

tions” on page 66

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

ured as “Interrupt on 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 and 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 synchronization

nop

; Read port pins

in r16,PINB

...

C Code Example

(1)

unsigned char i;

...

/* Define pull-ups and set outputs high */

/* Define directions for port pins */

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

DDRB = (1<<DDB3)|(1<<DDB2)|(1<<DDB1)|(1<<DDB0);

/* Insert nop for synchronization*/

_NOP();

/* Read port pins */

i = PINB;

...

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 ... 330 331

Komentáře k této Příručce

Žádné komentáře

Rainbow-electronics ATmega128L Uživatelský manuál Strana 65

Komentáře k této Příručce

Související produkty a manuály pro Senzory Rainbow-electronics ATmega128L