Se i __interrupt void UART_RX_interrupt( void ) och __interrupt void UART_TX_interrupt( void ).
Kod: Markera allt
// AVR306: Using the AVR UART in C
// Routines for interrupt controlled UART
// Last modified: 02-06-21
// Modified by: AR
/* Includes */
#include <io8515.h>
#include <ina90.h>
/* UART Buffer Defines */
#define UART_RX_BUFFER_SIZE 128 /* 2,4,8,16,32,64,128 or 256 bytes */
#define UART_TX_BUFFER_SIZE 128
#define UART_RX_BUFFER_MASK ( UART_RX_BUFFER_SIZE - 1 )
#if ( UART_RX_BUFFER_SIZE & UART_RX_BUFFER_MASK )
#error RX buffer size is not a power of 2
#endif
#define UART_TX_BUFFER_MASK ( UART_TX_BUFFER_SIZE - 1 )
#if ( UART_TX_BUFFER_SIZE & UART_TX_BUFFER_MASK )
#error TX buffer size is not a power of 2
#endif
/* Static Variables */
static unsigned char UART_RxBuf[UART_RX_BUFFER_SIZE];
static volatile unsigned char UART_RxHead;
static volatile unsigned char UART_RxTail;
static unsigned char UART_TxBuf[UART_TX_BUFFER_SIZE];
static volatile unsigned char UART_TxHead;
static volatile unsigned char UART_TxTail;
/* Prototypes */
void InitUART( unsigned char baudrate );
unsigned char ReceiveByte( void );
void TransmitByte( unsigned char data );
/* Main - a simple test program*/
void main( void )
{
InitUART( 11 ); /* Set the baudrate to 19,200 bps using a 3.6864MHz crystal */
_SEI(); /* Enable interrupts => enable UART interrupts */
for( ; ; ) /* Forever */
{
TransmitByte( ReceiveByte() ); /* Echo the received character */
}
}
/* Initialize UART */
void InitUART( unsigned char baudrate )
{
unsigned char x;
UBRR = baudrate; /* Set the baud rate */
/* Enable UART receiver and transmitter, and receive interrupt */
UCR = ( (1<<RXCIE) | (1<<RXEN) | (1<<TXEN) );
x = 0; /* Flush receive buffer */
UART_RxTail = x;
UART_RxHead = x;
UART_TxTail = x;
UART_TxHead = x;
}
/* Interrupt handlers */
#pragma vector=UART_RX_vect
__interrupt void UART_RX_interrupt( void )
{
unsigned char data;
unsigned char tmphead;
data = UDR; /* Read the received data */
/* Calculate buffer index */
tmphead = ( UART_RxHead + 1 ) & UART_RX_BUFFER_MASK;
UART_RxHead = tmphead; /* Store new index */
if ( tmphead == UART_RxTail )
{
/* ERROR! Receive buffer overflow */
}
UART_RxBuf[tmphead] = data; /* Store received data in buffer */
}
#pragma vector=UART_UDRE_vect
__interrupt void UART_TX_interrupt( void )
{
unsigned char tmptail;
/* Check if all data is transmitted */
if ( UART_TxHead != UART_TxTail )
{
/* Calculate buffer index */
tmptail = ( UART_TxTail + 1 ) & UART_TX_BUFFER_MASK;
UART_TxTail = tmptail; /* Store new index */
UDR = UART_TxBuf[tmptail]; /* Start transmition */
}
else
{
UCR &= ~(1<<UDRIE); /* Disable UDRE interrupt */
}
}
/* Read and write functions */
unsigned char ReceiveByte( void )
{
unsigned char tmptail;
while ( UART_RxHead == UART_RxTail ) /* Wait for incomming data */
;
tmptail = ( UART_RxTail + 1 ) & UART_RX_BUFFER_MASK;/* Calculate buffer index */
UART_RxTail = tmptail; /* Store new index */
return UART_RxBuf[tmptail]; /* Return data */
}
void TransmitByte( unsigned char data )
{
unsigned char tmphead;
/* Calculate buffer index */
tmphead = ( UART_TxHead + 1 ) & UART_TX_BUFFER_MASK; /* Wait for free space in buffer */
while ( tmphead == UART_TxTail );
UART_TxBuf[tmphead] = data; /* Store data in buffer */
UART_TxHead = tmphead; /* Store new index */
UCR |= (1<<UDRIE); /* Enable UDRE interrupt */
}
unsigned char DataInReceiveBuffer( void )
{
return ( UART_RxHead != UART_RxTail ); /* Return 0 (FALSE) if the receive buffer is empty */
}
