Пример #1
0
 void write_bit( bool x ){
    scl.set( 0 );
    wait_half_period();
    sda.set( x );
    scl.set( 1 );
    wait_half_period();
 }
   /// write and read to (and from) a spi chip
   //
   /// This function performs an n byte write-and-read operation on the
   /// SPI chip activated by the (active low) sel pin.
   ///
   /// When either writing or reading is not needed the corresponding
   /// argument can be a nullptr.
   void write_and_read( 
      pin_out & sel, 
      int n, 
      const byte data_out[], 
      byte data_in[] 
   ) override {

      sel.set( 0 );
      for( int i = 0; i < n; ++i ){
          
          byte d = 
             ( data_out == nullptr )
             ? 0 
             : *data_out++;
             
          for( int j = 0; j < 8; ++j ){
              mosi.set( ( d & 0x80 ) != 0 );
              wait_half_period();
              sclk.set( 1 );
              wait_half_period();
              d = d << 1;
              if( miso.get() ){
                 d |= 0x01;
              }
              sclk.set( 0 );              
          }
          
          if( data_in != nullptr ){
             *data_in++ = d;
          }
      }      
      wait_half_period();
      sel.set( 1 );
      wait_half_period();
   }      
Пример #3
0
 void write_stop(){
    scl.set( 0 );
    wait_half_period();   
    sda.set( 0 );
    wait_half_period();   
    scl.set( 1 );
    wait_half_period();   
    sda.set( 1 );
    wait_half_period();    
 }
Пример #4
0
 bool read_bit(){
    scl.set( 0 );
    sda.set( 1 );
    wait_half_period();  
    scl.set( 1 );
    wait_half_period();
    bool result = sda.get();
    wait_half_period();    
    return result;
 }       
Пример #5
0
 void write_start(){
    sda.set( 0 );
    wait_half_period();
    scl.set( 0 );
    wait_half_period(); 
 }