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 DigitalOut RXLed(LED2);
00033 DigitalOut TXLed(LED3);
00034 Timeout RXTimeout;
00035 Timeout TXTimeout;
00036 
00037 void RXTimeoutFunc(void)
00038 {
00039   RXLed = 0;
00040 }
00041 
00042 void TXTimeoutFunc(void)
00043 {
00044   TXLed = 0;
00045 }
00046 
00047 /* ----------------------- static functions ---------------------------------*/
00048 static void prvvUARTTxReadyISR( void );
00049 static void prvvUARTRxISR( void );
00050 static void prvvUARTISR( void );
00051 
00052 /* ----------------------- System Variables ---------------------------------*/
00053 Serial pc(USBTX, USBRX);            // Cam - mbed USB serial port
00054 
00055 Ticker simISR;                      // Cam - mbed ticker
00056                                     // we don't have the TX buff empty interrupt, so
00057                                     // we just interrupt every 1 mSec and read RX & TX
00058                                     // status to simulate the proper ISRs.
00059 
00060 static BOOL RxEnable, TxEnable;     // Cam - keep a static copy of the RxEnable and TxEnable
00061                                     // status for the simulated ISR (ticker)
00062 
00063 
00064 /* ----------------------- Start implementation -----------------------------*/
00065 // Cam - This is called every 1mS to simulate Rx character received ISR and
00066 // Tx buffer empty ISR.
00067 static void
00068 prvvUARTISR( void )
00069 {
00070     if (TxEnable)
00071     {
00072         if(pc.writeable())
00073             prvvUARTTxReadyISR();
00074     }        
00075     if (RxEnable)
00076     {
00077         if(pc.readable())
00078             prvvUARTRxISR();          
00079     }
00080 }
00081 
00082 void
00083 vMBPortSerialEnable( BOOL xRxEnable, BOOL xTxEnable )
00084 {
00085     /* If xRXEnable enable serial receive interrupts. If xTxENable enable
00086      * transmitter empty interrupts.
00087      */
00088     RxEnable = xRxEnable;
00089     TxEnable = xTxEnable;
00090 }
00091 
00092 BOOL
00093 xMBPortSerialInit( UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity )
00094 {
00095     simISR.attach_us(&prvvUARTISR,1000);    // Cam - attach prvvUARTISR to a 1mS ticker to simulate serial interrupt behaviour
00096                                             // 1mS is just short of a character time at 9600 bps, so quick enough to pick
00097                                             // up status on a character by character basis.
00098     return TRUE;
00099 }
00100 
00101 BOOL
00102 xMBPortSerialPutByte( CHAR ucByte )
00103 {
00104     /* Put a byte in the UARTs transmit buffer. This function is called
00105      * by the protocol stack if pxMBFrameCBTransmitterEmpty( ) has been
00106      * called. */
00107     pc.putc( ucByte);
00108     TXLed = 1;
00109     TXTimeout.attach(TXTimeoutFunc, 0.020);
00110     return TRUE;
00111 }
00112 
00113 BOOL
00114 xMBPortSerialGetByte( CHAR * pucByte )
00115 {
00116     /* Return the byte in the UARTs receive buffer. This function is called
00117      * by the protocol stack after pxMBFrameCBByteReceived( ) has been called.
00118      */
00119     * pucByte = pc.getc();
00120     RXLed = 1;
00121     RXTimeout.attach(RXTimeoutFunc, 0.020);
00122     return TRUE;
00123 }
00124 
00125 /* Create an interrupt handler for the transmit buffer empty interrupt
00126  * (or an equivalent) for your target processor. This function should then
00127  * call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that
00128  * a new character can be sent. The protocol stack will then call 
00129  * xMBPortSerialPutByte( ) to send the character.
00130  */
00131 static void prvvUARTTxReadyISR( void )
00132 {
00133     pxMBFrameCBTransmitterEmpty(  );
00134 }
00135 
00136 /* Create an interrupt handler for the receive interrupt for your target
00137  * processor. This function should then call pxMBFrameCBByteReceived( ). The
00138  * protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
00139  * character.
00140  */
00141 static void prvvUARTRxISR( void )
00142 {
00143     pxMBFrameCBByteReceived(  );
00144 }
00145 
00146