16bit seriell in 16bit Variable auslesen

/* Function:  uint8_t CPLD_u8ReadKeys(void)

Description: serially reads one port value (1 bit) and compose result byte value */ 

uint8_t CPLD_u8ReadKeys(void)

{

  uint8_t u8Result;

  uint8_t u8Index;

  DDRC  |= (1<<CPLD_nSerCLK);             /* SerCLK as output */

  DDRC  |= (1<<CPLD_nSerEN);              /* SerEN as output */

  DDRC  |= (1<<CPLD_nSerRDWR);            /* SerRDWR as output */

  DDRD  &= (~(1<<CPLD_nSerDATA));         /* SerDATA as input */

  PORTC &= (~(1<<CPLD_nSerRDWR));         /* RDWR=0, read from CPLD operation */

  PORTC |= (1<<CPLD_nSerEN);              /* EN=1, serial clock disabled, read keys to parallel register */

  PORTC &= (~(1<<CPLD_nSerEN));           /* EN=0, serial clock enabled */

  u8Result = 0;                           /* reset the return value */

  for (u8Index=0; u8Index < 8; u8Index++)

  {

    u8Result>>=1;

    PORTC |= (1<<CPLD_nSerCLK);            /* SerCLK = 1 */

    PORTC &= (~(1<<CPLD_nSerCLK));         /* SerCLK = 0 */

    u8Result |= PIND & (1<<CPLD_nSerDATA); /* Insert the port value to u8Result and shift left 1 position */

  }

  return (u8Result);

}