Передача даних через UART в AVR. Урок AVR 9

 # include <mega8.h>  
 void main ( void )  
 {  
 char date = 0 ;  
   PORTC = 0x00;  
 DDRC = 0x01;    
 // USART initialization  
 // Communication Parameters : 8 Data , 1 Stop , No Parity  
 // USART Receiver : On  
 // USART Transmitter : On  
 // USART Mode : Asynchronous  
 // USART Baud Rate : 9600  
 UCSRA = 0x00;  
 UCSRB = 0x18 ;  
 UCSRC = 0x86 ;  
 UBRRH = 0x00;  
 UBRRL = 0x33 ;  
   while ( 1 )  
 {  
 date = UDR ;  
  
 if ( date == '1 ' ) PORTC.0 = 1 ;  
 if ( date == '0 ') PORTC.0 = 0 ;  
 } ;  
 }  
 

 # include <mega8.h>  
 # ifndef RXB8  
 # define RXB8 1  
 # endif    
 # ifndef TXB8  
 # define TXB8 0  
 # endif    
 # ifndef UPE  
 # define UPE 2  
 # endif    
 # ifndef DOR  
 # define DOR 3  
 # endif    
 # ifndef FE  
 # define FE 4  
 # endif    
 # ifndef UDRE  
 # define UDRE 5  
 # endif    
 # ifndef RXC  
 # define RXC 7  
 # endif    
 # define FRAMING_ERROR ( 1 < < FE)  
 # define PARITY_ERROR ( 1 < < UPE )  
 # define DATA_OVERRUN ( 1 < < DOR )  
 # define DATA_REGISTER_EMPTY ( 1 < < UDRE )  
 # define RX_COMPLETE ( 1 < < RXC )    
      // USART Receiver buffer  
 # define RX_BUFFER_SIZE 8   char rx_buffer [ RX_BUFFER_SIZE ] ;    
 # if RX_BUFFER_SIZE < 256   unsigned char rx_wr_index , rx_rd_index , rx_counter ;  
 # else   unsigned int rx_wr_index , rx_rd_index , rx_counter ;  
 # endif
     // This flag is set on USART Receiver buffer overflow   bit rx_buffer_overflow ;    
 // USART Receiver interrupt service routine   interrupt [ USART_RXC ] void usart_rx_isr ( void )  
 {   char status , data ;   status = UCSRA ;  
 data = UDR ;  
 if ( ( status & ( FRAMING_ERROR | PARITY_ERROR | DATA_OVERRUN )) == 0 )  
 {  
 rx_buffer [ rx_wr_index ] = data ;  
 if ( + + rx_wr_index == RX_BUFFER_SIZE ) rx_wr_index = 0 ;  
 if ( + + rx_counter == RX_BUFFER_SIZE )  
 {  
 rx_counter = 0 ;  
 rx_buffer_overflow = 1 ;  
 } ;  
 } ;  
 if ( data == '1 ' ) PORTC.0 = 1 ;  
 if ( data == '0 ') PORTC.0 = 0 ;  
 }  
  
 # include <stdio.h>    
 void main ( void )  
 {  
 // Port C initialization  
 PORTC = 0x00;  
 DDRC = 0x01;    
 // USART initialization  
 // Communication Parameters : 8 Data , 1 Stop , No Parity  
 // USART Receiver : On  
 // USART Transmitter : Off  
 // USART Mode : Asynchronous  
 // USART Baud Rate : 9600  
 UCSRA = 0x00;  
 UCSRB = 0x90 ;  
 UCSRC = 0x86 ;  
 UBRRH = 0x00;  
 UBRRL = 0x33 ;  
   / / Global enable interrupts  
 # asm ( " sei " )  
   while ( 1 )  
 {  
 } ;  
 }