portserial.cpp

00001 /*
00002  * FreeModbus Libary: BARE Port
00003  * Copyright (C) 2006 Christian Walter <wolti@sil.at>
00004  *
00005  * This library is free software; you can redistribute it and/or
00006  * modify it under the terms of the GNU Lesser General Public
00007  * License as published by the Free Software Foundation; either
00008  * version 2.1 of the License, or (at your option) any later version.
00009  *
00010  * This library is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013  * Lesser General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU Lesser General Public
00016  * License along with this library; if not, write to the Free Software
00017  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00018  *
00019  * File: $Id: portserial.c,v 1.1 2006/08/22 21:35:13 wolti Exp $
00020  */
00021 
00022 /* ----------------------- System includes ----------------------------------*/
00023 #include "mbed.h"                   // Cam
00024 
00025 /* ----------------------- Platform includes --------------------------------*/
00026 #include "port.h"
00027 
00028 /* ----------------------- Modbus includes ----------------------------------*/
00029 #include "mb.h"
00030 #include "mbport.h"
00031 
00032 
00033 /* ----------------------- static functions ---------------------------------*/
00034 static void prvvUARTTxReadyISR( void );
00035 static void prvvUARTRxISR( void );
00036 static void prvvUARTISR( void );
00037 
00038 /* ----------------------- System Variables ---------------------------------*/
00039 Serial pc(USBTX, USBRX);            // Cam - mbed USB serial port
00040 
00041 Ticker simISR;                      // Cam - mbed ticker
00042                                     // we don't have the TX buff empty interrupt, so
00043                                     // we just interrupt every 1 mSec and read RX & TX
00044                                     // status to simulate the proper ISRs.
00045 
00046 static BOOL RxEnable, TxEnable;     // Cam - keep a static copy of the RxEnable and TxEnable
00047                                     // status for the simulated ISR (ticker)
00048 
00049 
00050 /* ----------------------- Start implementation -----------------------------*/
00051 // Cam - This is called every 1mS to simulate Rx character received ISR and
00052 // Tx buffer empty ISR.
00053 static void
00054 prvvUARTISR( void )
00055 {
00056     if (TxEnable)
00057         if(pc.writeable())
00058             prvvUARTTxReadyISR();
00059             
00060     if (RxEnable)
00061         if(pc.readable())
00062             prvvUARTRxISR();          
00063 }
00064 
00065 void
00066 vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )
00067 {
00068     /* If xRXEnable enable serial receive interrupts. If xTxENable enable
00069      * transmitter empty interrupts.
00070      */
00071     RxEnable = xRxEnable;
00072     TxEnable = xTxEnable;
00073 }
00074 
00075 BOOL
00076 xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
00077 {
00078     simISR.attach_us(&prvvUARTISR,1000);    // Cam - attach prvvUARTISR to a 1mS ticker to simulate serial interrupt behaviour
00079                                             // 1mS is just short of a character time at 9600 bps, so quick enough to pick
00080                                             // up status on a character by character basis.
00081     return TRUE;
00082 }
00083 
00084 BOOL
00085 xMBPortSerialPutByte( CHAR ucByte )
00086 {
00087     /* Put a byte in the UARTs transmit buffer. This function is called
00088      * by the protocol stack if pxMBFrameCBTransmitterEmpty( ) has been
00089      * called. */
00090     pc.putc( ucByte);
00091     return TRUE;
00092 }
00093 
00094 BOOL
00095 xMBPortSerialGetByte( CHAR * pucByte )
00096 {
00097     /* Return the byte in the UARTs receive buffer. This function is called
00098      * by the protocol stack after pxMBFrameCBByteReceived( ) has been called.
00099      */
00100     * pucByte = pc.getc();
00101     return TRUE;
00102 }
00103 
00104 /* Create an interrupt handler for the transmit buffer empty interrupt
00105  * (or an equivalent) for your target processor. This function should then
00106  * call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that
00107  * a new character can be sent. The protocol stack will then call 
00108  * xMBPortSerialPutByte( ) to send the character.
00109  */
00110 static void prvvUARTTxReadyISR( void )
00111 {
00112     pxMBFrameCBTransmitterEmpty(  );
00113 }
00114 
00115 /* Create an interrupt handler for the receive interrupt for your target
00116  * processor. This function should then call pxMBFrameCBByteReceived( ). The
00117  * protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
00118  * character.
00119  */
00120 static void prvvUARTRxISR( void )
00121 {
00122     pxMBFrameCBByteReceived(  );
00123 }
00124 
00125