at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 70

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

10.2.5
70
AT90PWM81
Digital Input Enable and Sleep Modes
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
ger. The signal denoted SLEEP in the figure, is set by the MCU Sleep Controller in Power-down mode,
and Standby mode to avoid high power consumption if some input signals are left floating, or have an ana-
log 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 various other alternate func-
tions as described in
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
C Code Example
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 */
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. 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.
Figure
r16, (1<<PB7)|(1<<PB6)|(1<<PB1)|(1<<PB0)
r17, (1<<DDB3)|(1<<DDB2)|(1<<DDB1)|(1<<DDB0)
PORTB, r16
DDRB, r17
r16, PINB
10-2, the digital input signal can be clamped to ground at the input of the schmitt-trig-
“Alternate Port Functions” on page
CC
(1)
/2.
71.
7734M–AVR–03/10