Interrupt Access without Hardware

hi,
i able shut down receiver save current, can't figure out how wake without bringing rx pin 2 gnd.


rx code:

code: [select]

// **** includes *****
#include <spi.h>
#include "nrf24l01.h"
#include "rf24.h"
#include "printf.h"
#include <avr/sleep.h>

int inputs[3];

rf24 radio(9, 10);
const uint64_t pipe = 0xe8e8f0f0e1ll;

// use pin 2 wake pin
const int wakeuppin = 2;

void wakeup()
{
  // cancel sleep precaution
  sleep_disable();
  // must pin stay low while
  detachinterrupt (0);
}

void setup()
{
  serial.begin(57600);
  printf_begin();
  radio.begin();
  radio.setdatarate(rf24_250kbps);
  radio.setpalevel(rf24_pa_min);
  radio.setchannel(3);
  radio.printdetails();
  radio.openreadingpipe(1, pipe);
  radio.startlistening();
  pinmode(3, output);
  pinmode(4, output);
  pinmode(5, output);
  pinmode(6, output);
  pinmode(7, output);
  pinmode(8, output);
  pinmode(wakeuppin, input_pullup);
}

void loop()
{

  if (radio.available())
  {
    while (radio.available())
    {
      radio.read( &inputs, sizeof(inputs) );
      //serial.println ("available");
      digitalwrite(5, high);
      if (inputs[0] == 0)
      {
        digitalwrite(5, low);
        radio.powerdown();
        // allow wake pin trigger interrupt on low.
        set_sleep_mode (sleep_mode_pwr_down);
        sleep_enable();

        // not interrupt before go sleep, or the
        // isr detach interrupts , won't wake.
        nointerrupts ();

        // called when pin d2 goes low
        attachinterrupt (0, wakeup, low);

        interrupts();
        sleep_cpu();
      }
    }
    //radio.startlistening();
    //radio.powerup();
  }
  else
  {
    radio.startlistening();
    radio.powerup();
  }
}


i read nrf24l01 cannot find examples uses

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