isqc_comm.X/isqc_tools.h
void isqc_nack()
{
    isqc_wait();
    ACKDT = 1; // (1,0) = ('nack', 'ack')
    ACKEN = 1; //send 'nack'
}
/* 7. NACK
 * Master receive mode only */
7. NACK
Master receive mode only
7 . NACK Master receive mode only
void isqc_nack()
{
    isqc_wait();
    ACKDT = 1; 
    ACKEN = 1; 
}
void isqc_nack ( ) { isqc_wait ( ) ; ACKDT = 1 ; ACKEN = 1 ; }
7.
7 .
// (1,0) = ('nack', 'ack') //send 'nack'