title: Avr Problem: in spi, spdr register is 8 bit but my number is 16 bit
body: <p>I work with atmega16, in both side master and slave. 
  I want to send a number between 100-999 that entered by keypad to the slave. 
  Numbers are 16 bit, but spdr register is 8 bit, so I send first lsb then msb bits. This works well and I send my number correctly. </p>
  
  <p>But my problem is in slave side:
  I enabled interrupt spie in slave side so each spdr received from master took as a interrupt and goes to ISR function. But because of my number is 16 bit, I want to take each 16 bit or two byte as a interrupt. What should i do?</p>