6 digital input enable and sleep modes, 7 unconnected pins, Atmega128rfa1 – Rainbow Electronics ATmega128RFA1 User Manual
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8266A-MCU Wireless-12/09
ATmega128RFA1
Assembly Code Example
(1)
…
; Define pull-ups and set outputs high
; Define directions for port pins
ldi r16,(1< ldi r17,(1< out PORTB,r16 out DDRB,r17 ; Insert nop for synchronization nop ; Read port pins in r16,PINB … C Code Example unsigned char i; … /* Define pull-ups and set outputs high */ /* Define directions for port pins */ PORTB = (1< DDRB = (1< /* Insert nop for synchronization*/ __no_operation(); /* Read port pins */ i = PINB; … 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, 14.2.6 Digital Input Enable and Sleep Modes As shown in , 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 DEVDD /2. SLEEP is overridden for port pins enabled as external interrupt pins. If the external . If a logic high level (“one”) is present on an asynchronous external interrupt pin 14.2.7 Unconnected Pins If some pins are unused, it is recommended to ensure that these pins have a defined
defining bit 2 and 3 as low and redefining bits 0 and 1 as strong high drivers.
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
interrupt request is not enabled, SLEEP is active also for these pins. SLEEP is also
overridden by various other alternate functions as described in
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 mode, as the clamping in these
sleep mode produces the requested logic change.
level. Even though most of the digital inputs are disabled in the deep sleep modes as