root/webserver/example/EnergyMeters/Source/serial.c

/*
        FreeRTOS.org V5.0.2 - Copyright (C) 2003-2008 Richard Barry.

        This file is part of the FreeRTOS.org distribution.

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        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        FreeRTOS.org is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with FreeRTOS.org; if not, write to the Free Software
        Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

        A special exception to the GPL can be applied should you wish to distribute
        a combined work that includes FreeRTOS.org, without being obliged to provide
        the source code for any proprietary components.  See the licensing section
        of http://www.FreeRTOS.org for full details of how and when the exception
        can be applied.

    ***************************************************************************
    ***************************************************************************
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        Please ensure to read the configuration and relevant port sections of the
        online documentation.

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*/


/*
        BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
*/

/* Standard includes. */
#include <stdlib.h>

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"

#include "semphr.h"

/* Demo application includes. */
#include "serial.h"


/*-----------------------------------------------------------*/

/* Constants to setup and access the UART. */
#define serDLAB                                                 ( ( unsigned portCHAR ) 0x80 )
#define serENABLE_INTERRUPTS                    ( ( unsigned portCHAR ) 0x03 )
#define serNO_PARITY                                    ( ( unsigned portCHAR ) 0x00 )
#define ser1_STOP_BIT                                   ( ( unsigned portCHAR ) 0x00 )
#define ser8_BIT_CHARS                                  ( ( unsigned portCHAR ) 0x03 )
#define serFIFO_ON                                              ( ( unsigned portCHAR ) 0x01 )
#define serCLEAR_FIFO                                   ( ( unsigned portCHAR ) 0x06 )
#define serWANTED_CLOCK_SCALING                 ( ( unsigned portLONG ) 16 )

/* Constants to setup and access the VIC. */
#define serU3VIC_CHANNEL                                ( ( unsigned portLONG ) 0x0006 )
#define serU3VIC_CHANNEL_BIT                    ( ( unsigned portLONG ) 0x0040 )
#define serU3VIC_ENABLE                                 ( ( unsigned portLONG ) 0x0020 )
#define serCLEAR_VIC_INTERRUPT                  ( ( unsigned portLONG ) 0 )

/* Constants to determine the ISR source. */
#define serSOURCE_THRE                                  ( ( unsigned portCHAR ) 0x02 )
#define serSOURCE_RX_TIMEOUT                    ( ( unsigned portCHAR ) 0x0c )
#define serSOURCE_ERROR                                 ( ( unsigned portCHAR ) 0x06 )
#define serSOURCE_RX                                    ( ( unsigned portCHAR ) 0x04 )
#define serINTERRUPT_SOURCE_MASK                ( ( unsigned portCHAR ) 0x0f )

/* Misc. */
#define serINVALID_QUEUE                                ( ( xQueueHandle ) 0 )
#define serHANDLE                                               ( ( xComPortHandle ) 1 )
#define serNO_BLOCK                                             ( ( portTickType ) 0 )

/*-----------------------------------------------------------*/

/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
static volatile portLONG lTHREEmpty = pdFALSE;

/*-----------------------------------------------------------*/

/* The ISR.  Note that this is called by a wrapper written in the file
SerialISR.s79.  See the WEB documentation for this port for further
information. */
void vSerialISR( void );


extern void ( vUART3_ISR_Wrapper )( void );
extern unsigned int uart3TxRunning;




/* The interrupt entry point. */
void vUART3_ISR_Wrapper( void ) __attribute__((naked));

/* The function that actually performs the interrupt processing.  This must be 
separate to the wrapper to ensure the correct stack frame is set up. */
void vSerialISR( void );


void vSerialISR( void )
{
signed portCHAR cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

        /* What caused the interrupt? */
        switch( U3IIR & serINTERRUPT_SOURCE_MASK )
        {
                case serSOURCE_ERROR :  /* Not handling this, but clear the interrupt. */
                                                                cChar = U3LSR;
                                                                break;

                case serSOURCE_THRE     :       /* The THRE is empty.  If there is another
                                                                character in the Tx queue, send it now. */

                                  if (uart3TxRunning == 0)
                                  {
                                    RXD_RS485(); /* we are done sending, we have to receive now. */
                                  }
                                  else
                                  {
                                    TXD_RS485(); /* we are still sending */
                                  }
#if 0                                                     
                                                                if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
                                                                {
                                                                        //TXD_RS485();  /* send */
                                                                        U3THR = cChar;
                                                                        RXD_RS485();    
                                                                }
                                                                else
                                                                {
                                                                        /* There are no further characters
                                                                        queued to send so we can indicate
                                                                        that the THRE is available. */
                                                                        lTHREEmpty = pdTRUE;

                                                                        /* the queue is empty, the FIFO is empty. switch to RXD,
                                                                         * so we can receive the response from the network. 
                                                                         */
                                                                        RXD_RS485();

                                                                }
                                                                break;

#endif


                case serSOURCE_RX_TIMEOUT :
                case serSOURCE_RX       :       /* A character was received.  Place it in
                                                                the queue of received characters. */
                                                                cChar = U3RBR;
                                                                xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
                                                                break;

                default                         :       /* There is nothing to do, leave the ISR. */
                                                                break;
        }


        /* Clear the ISR in the VIC. */
        VICVectAddr = serCLEAR_VIC_INTERRUPT;       


        /* Exit the ISR.  If a task was woken by either a character being received
        or transmitted then a context switch will occur. */

        portYIELD_FROM_ISR();
        //portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );


}
/*-----------------------------------------------------------*/

void vUART3_ISR_Wrapper( void )
{
        /* Save the context of the interrupted task. */
        portSAVE_CONTEXT();

        /* Call the handler function.  This must be separate from the wrapper
        function to ensure the correct stack frame is set up. */
        vSerialISR();

        /* Restore the context of whichever task is going to run next. */
        portRESTORE_CONTEXT();
}





/*-----------------------------------------------------------*/

xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{


  unsigned int baud = 57600;
  unsigned int divisor = get_uart_clk(3, OSCILLATOR_CLOCK_FREQUENCY) / (16 * baud);



unsigned portLONG ulDivisor, ulWantedClock;
xComPortHandle xReturn = serHANDLE;
extern void ( vSerialISREntry) ( void );

        /* Create the queues used to hold Rx and Tx characters. */
        xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
        xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );

        /* Initialise the THRE empty flag. */
        lTHREEmpty = pdTRUE;

        if(
                ( xRxedChars != serINVALID_QUEUE ) &&
                ( xCharsForTx != serINVALID_QUEUE ) &&
                ( ulWantedBaud != ( unsigned portLONG ) 0 )
          )
        {
                portENTER_CRITICAL();
                {
                  /* Setup the baud rate:  Calculate the divisor value. */
                  ulWantedClock = ulWantedBaud * serWANTED_CLOCK_SCALING;
                  ulDivisor = configCPU_CLOCK_HZ / ulWantedClock;


                  // xxxx xx1x xxxx xxxx xxxx xxxx xxxx xxxx
                  PCONP   |= 0x02000000;                                                                        // UART3 Power-ON
                
                
                
                /* Configure UART */
                
                
                 U3LCR = 0x83;                                                                  // 8 bits, no Parity, 1 Stop bit
                
                 U3DLL = divisor & 0xFF;
                
                 U3DLM = (divisor >> 8) & 0xFF;
                
                  /* Turn on the FIFO's and clear the buffers. */
                  U3FCR = ( serFIFO_ON | serCLEAR_FIFO );
                
                 
                 U3LCR = 0x03;  
                
                  /* Setup the VIC for the UART. */
                  VICVectAddr29 = (portLONG) vUART3_ISR_Wrapper; /* UART3 interrupt handler */
                  VICIntEnable |= (1<<29); /* Enable VIC index-29 (sUART3) */
                  
                  /* Enable UART3 interrupts. */
                  U3IER |= serENABLE_INTERRUPTS;
                }
                portEXIT_CRITICAL();

                xReturn = ( xComPortHandle ) 1;
        }
        else
        {
                xReturn = ( xComPortHandle ) 0;
        }

        return xReturn;
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
{
        /* The port handle is not required as this driver only supports UART3. */
        ( void ) pxPort;

        /* Get the next character from the buffer.  Return false if no characters
        are available, or arrive before xBlockTime expires. */
        if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
        {
                return pdTRUE;
        }
        else
        {
                return pdFALSE;
        }
}
/*-----------------------------------------------------------*/

void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
{
signed portCHAR *pxNext;

        /* NOTE: This implementation does not handle the queue being full as no
        block time is used! */

        /* The port handle is not required as this driver only supports UART0. */
        ( void ) pxPort;
        ( void ) usStringLength;

        /* Send each character in the string, one at a time. */
        pxNext = ( signed portCHAR * ) pcString;
        while( *pxNext )
        {
                xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
                pxNext++;
        }
}
/*-----------------------------------------------------------*/

signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
{
signed portBASE_TYPE xReturn;

        /* The port handle is not required as this driver only supports UART3. */
        ( void ) pxPort;

        portENTER_CRITICAL();
        {
                /* Is there space to write directly to the UART? */
                if( lTHREEmpty == ( portLONG ) pdTRUE )
                {
                        /* We wrote the character directly to the UART, so was
                        successful. */
                        lTHREEmpty = pdFALSE;
                        //TXD_RS485();  
                        U3THR = cOutChar;
                        //RXD_RS485();  
                        xReturn = pdPASS;
                }
                else
                {
                        /* We cannot write directly to the UART, so queue the character.
                        Block for a maximum of xBlockTime if there is no space in the
                        queue.  It is ok to block within a critical section as each
                        task has it's own critical section management. */
                        xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );

                        /* Depending on queue sizing and task prioritisation:  While we
                        were blocked waiting to post interrupts were not disabled.  It is
                        possible that the serial ISR has emptied the Tx queue, in which
                        case we need to start the Tx off again. */
                        if( lTHREEmpty == ( portLONG ) pdTRUE )
                        {
                                xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
                                lTHREEmpty = pdFALSE;
                                //TXD_RS485();  
                                U3THR = cOutChar;
                                //RXD_RS485();
                        }
                }
        }
        portEXIT_CRITICAL();

        return xReturn;
}
/*-----------------------------------------------------------*/