unsigned char ds_present(){
//ds_pin_get();
// give the device time to get back to the 'rest' state
ds_pin_set( 1 );
delay( 2000 );
// test for stuck-at-0
if( ! ds_pin_get() ){
uart_put_string("\ntest stuck at 0");
return 0;
}
// request a presence pulse
ds_pin_pulse( 1000 );
// test for the presence pulse
delay( 30 );
if( ds_pin_get() ){
uart_put_string("\npresent pulse");
return 0;
}
// test whether the presence pulse ends
delay( 1000 );
if( ! ds_pin_get() ){
uart_put_string("\npresence pulse doesn't end.");
return 0;
}
// all tests succeeded
return 1;
}
unsigned char ds_receive_bit( void ){
unsigned char x;
ds_pin_set(0);
x = ds_pin_get();
delay( 100 );
return x;
}
unsigned char ds_present(){
// give the device time to get back to the 'rest' state
ds_pin_set( 1 );
delay( 2000 );
// test for stuck-at-0
if( ! ds_pin_get() ){ return 0; }
// request a presence pulse
ds_pin_pulse( 1000 );
// test for the presence pulse
delay( 30 );
if( ds_pin_get() ){ return 0; }
// test whether the presence pulse ends
delay( 1000 );
if( ! ds_pin_get() ){ return 0; }
// all tests succeeded
return 1;
}
void ds_pin_pulse( unsigned long long int t ){
ds_pin_set( 0 );
delay( t );
ds_pin_set( 1 );
}