int pop_buffer( unsigned char* head, unsigned char** tail,
unsigned char* buff, unsigned char* data, int max_len )
{
unsigned char* local_tail;
unsigned char* local_head = head;
int cnt = 0;
BSP_CRITICAL_STATEMENT( local_tail = *tail );
/* if the buffer is empty or no data requested */
if( local_tail == local_head || max_len <= 0 )
return 0; /* indicate so */
do /* retrieve the data from the buffer */
{
if( local_tail == buff + RX_TX_BUFFER_SIZE ) /* if wrapping around */
local_tail = buff; /* reset pointer */
*data++ = *local_tail++; /* copy data from buffer */
/* while the user needs more data and there is data left in the fifo */
} while( ++cnt < max_len && local_tail != local_head );
BSP_CRITICAL_STATEMENT( *tail = local_tail ); /* update reference value */
return cnt; /* return number of characters retrieved from the buffer */
}
bool push_buffer( unsigned char** head, unsigned char* tail,
unsigned char* buff, unsigned char* data, int len )
{
unsigned char* local_head;
unsigned char* local_tail = tail;
BSP_CRITICAL_STATEMENT( local_head = *head );
/* if no room in the buffer */
if( buffer_free_space( local_head, local_tail ) < len )
return false; /* indicate failure to enqueue message */
/* there is room for the data, put in the buffer */
do /* put the data in the buffer */
{
if( local_head == buff + RX_TX_BUFFER_SIZE ) /* if wrapping around */
local_head = buff; /* reset pointer */
*local_head++ = *data++; /* copy over this byte of data */
} while( --len > 0 ); /* copy all the data to the buffer */
BSP_CRITICAL_STATEMENT( *head = local_head ); /* update reference value */
return true;
}
/******************************************************************************
* @fn uart_rx_irq
*
* @brief RX interrupt service routine
*
* input parameters
*
* output parameters
*
* @return
*/
void uart_rx_irq( void )
{
uart_put_rx_data_type handler;
/* read in the received data, this will clear the interrupt also */
unsigned char c = UART_RECEIVE( UART_NUMBER_1, UART1_LOCATION );
BSP_CRITICAL_STATEMENT( handler = uart_rx_handler );
if( handler != NULL ) /* if a handler exists to receive data */
if( ( *handler)( c ) == false ) /* if the user is done receiveing */
/* indicate the receiver is available */
BSP_CRITICAL_STATEMENT( uart_rx_handler = NULL );
return;
}
// the isr's...
static void uart_tx_irq( void )
{
unsigned char c;
{
uart_get_tx_data_type handler;
BSP_CRITICAL_STATEMENT( handler = uart_tx_handler );
// if not currently in suspend mode and a handler exists
if( uart_tx_suspend == false && handler != NULL )
{
if( (*handler)( &c ) != false ) // if data available, reset the interrupt
{
UART_SEND( UART_NUMBER, UART_LOCATION, c ); // send the byte
}
else // if no data suspend transmission
{
uart_tx_message_suspend( handler );
UART_IRQ_FLAG_SET( UART_NUMBER, UART_LOCATION, TX );
}
}
else
{
bspIState_t istate;
BSP_ENTER_CRITICAL_SECTION( istate );
// if we are in suspended mode or we just sent an xon or xoff character
// while transmits were disabled or the message has been completely sent,
// then simply disable irq's so we don't get stuck in an infinite loop
UART_IRQ_DISABLE( UART_NUMBER, UART_LOCATION, TX );
UART_IRQ_FLAG_SET( UART_NUMBER, UART_LOCATION, TX );
BSP_EXIT_CRITICAL_SECTION( istate );
}
}
return;
}
bool tx0_handler( unsigned char* c )
{
bool status;
unsigned char* head;
/* get current state of head pointer */
BSP_CRITICAL_STATEMENT( head = tx0_head );
/* get data off of the transmit buffer */
pop_buffer( head, &tx0_tail, tx0_buff, c, 1 );
/* check status of buffer */
BSP_CRITICAL_STATEMENT( status = tx0_head != tx0_tail );
return status; /* indicate if this is the last byte in the buffer */
}
static void uart_rx_irq( void )
{
uart_put_rx_data_type handler;
// read in the received data, this will clear the interrupt also
unsigned char c = UART_RECEIVE( UART_NUMBER, UART_LOCATION );
BSP_CRITICAL_STATEMENT( handler = uart_rx_handler );
if( handler != NULL ) // if a handler exists to receive data
if( ( *handler)( c ) == false ) // if the user is suspending
uart_rx_message_suspend( handler );
return;
}
bool tx0_send( const void* data, size_t len )
{
bool status;
unsigned char* tail;
/* get current state of tail pointer */
BSP_CRITICAL_STATEMENT( tail = tx0_tail );
/* put data into transmit buffer */
status = push_buffer( &tx0_head, tail, tx0_buff, (unsigned char*)data, len );
if( status != false ) /* if data was put in the buffer properly */
uart0_tx_message( tx0_handler ); /* notify the irq that data is ready to send */
return status; /* return status */
}
/******************************************************************************
* @fn uart1_tx_irq
*
* @brief TX interrupt service routine
*
* input parameters
*
* output parameters
*
* @return
*/
void uart0_tx_irq( void )
{
unsigned char c;
uart_get_tx_data_type handler;
BSP_CRITICAL_STATEMENT( handler = uart0_tx_handler );
/* if a handler exists */
if( handler != NULL )
{
if( (*handler)( &c ) != false ) /* if this is not the last byte to send */
{
bspIState_t intState;
BSP_ENTER_CRITICAL_SECTION( intState );
/* only reset the interrupt flag if we have additional data to send
* that way, if we are done then the interrupt is still pending and
* will be immediately entered upon re-enabling it.*/
UART_IRQ_FLAG_CLR( UART_NUMBER_0, UART0_LOCATION, TX ); /* eset the interrupt */
BSP_EXIT_CRITICAL_SECTION( intState );
}
else
{
bspIState_t intState;
BSP_ENTER_CRITICAL_SECTION( intState );
/* we're done sending data. since we left the interrupt pending,
* disable it so we don't re-enter the isr. the interrupt will be
* re-enabled when there is another message to send. */
UART_IRQ_DISABLE( UART_NUMBER_0, UART0_LOCATION, TX );
/* no more data to send, reset the handler to flag not busy */
uart0_tx_handler = NULL;
BSP_EXIT_CRITICAL_SECTION( intState );
}
UART_SEND( UART_NUMBER_0, UART0_LOCATION, c ); /* send the byte */
}
else /* if no handler exists?!?!?!? */
/* something went wrong, disable interrupts so we don't get stuck here */
UART_IRQ_DISABLE( UART_NUMBER_0, UART0_LOCATION, TX );
return;
}
bool rx_handler( unsigned char c )
{
unsigned char* tail;
/* get current state of tail pointer */
BSP_CRITICAL_STATEMENT( tail = rx_tail );
/* put data onto the receive buffer */
push_buffer( &rx_head, tail, rx_buff, &c, 1 );
#if( defined UART_HARDWARE_HANDSHAKE_IN_SOFTWARE )
/* if we need to hold off the remote transmitter */
if( rx_peek( ) >= RX_TX_BUFFER_THROTTLE_LIMIT )
UART_ASSERT_RTS( UART_RTS_ASSERTED ); /* assert the RTS line */
#endif
return true; /* always accept data received from the uart */
}
int rx_receive( void* data, int max_len )
{
int cnt;
unsigned char* head;
/* get current state of head pointer */
BSP_CRITICAL_STATEMENT( head = rx_head );
/* retrieve data from buffer */
cnt = pop_buffer( head, &rx_tail, rx_buff, data, max_len );
#if( defined UART_HARDWARE_HANDSHAKE_IN_SOFTWARE )
/* if we need to hold off the remote transmitter */
if( rx_peek( ) < RX_TX_BUFFER_THROTTLE_LIMIT )
UART_ASSERT_RTS( UART_RTS_DEASSERTED ); /* deassert the RTS line */
#endif
return cnt; /* indicate the number of bytes retrieved from the buffer */
}
