keypad sleep

good afternoon,

i'm learning use sleep modes in arduino, have problem can not solve.
i have arduino, lcd shift register, , keypad.

click on various number , when click on arduino 3 goes sleep.
the problem when wake arduino deletes message screen, keypad not work. click on numbers not appear on screen.

i wonder i'm doing wrong?

quote

#include <shiftlcd.h>
#include <keypad.h>
#include <avr/power.h>
#include <avr/sleep.h>
int wakepin = 2;

shiftlcd lcd(19, 17, 18);
const byte rows = 4; //four rows
const byte cols = 4; //three columns
char keys[rows][cols] = {
  {'d','#','0','*'},
  {'c','9','8','7'},
  {'b','6','5','4'},
  {'a','3','2','1'},
};
byte rowpins[rows] = {8, 7, 6, 5}; //connect row pinouts of keypad
byte colpins[cols] = {12, 11, 10, 9}; //connect column pinouts of keypad

keypad keypad = keypad( makekeymap(keys), rowpins, colpins, rows, cols );

void setup()
{
   lcd.begin(16, 2);
  //setup pushbutoon
  pinmode(wakepin, input);
  digitalwrite(wakepin, high);

  attachinterrupt(0, wakeupnow, low);
}
void loop()
{
char key = keypad.getkey();

    if (key!= no_key){
        lcd.print(key);
    if (key == '3' ){
          sleepnow();
        }
    }
}
   
void wakeupnow()
{
lcd.clear();

}

void sleepnow()
{
    set_sleep_mode(sleep_mode_pwr_down);
    sleep_enable();
   sleep_cpu ();
    attachinterrupt(0,wakeupnow, low);
    sleep_mode();
    sleep_disable();
    detachinterrupt(0);

}

the keypad library works polling pins if microcontroller asleep keypad asleep.  you'll need wire diodes , connect pins external interrupt.  crossroads added hardware interrupt keypad , if scroll down 2 more posts you'll see code go it.

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