Contiki 2.6

ctsrts-sensor.c

00001 /*
00002  * Copyright (c) 2005, Swedish Institute of Computer Science
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the Institute nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  *
00029  * This file is part of the Contiki operating system.
00030  *
00031  * @(#)$Id: ctsrts-sensor.c,v 1.4 2010/02/08 00:00:45 nifi Exp $
00032  */
00033 
00034 /**
00035  * RTS/CTS (Request to Send/Clear to Send) are the signals used for hardware
00036  * flow control. By setting the RTS line to "ON" the host tells the connected
00037  * device that it is ready to receive data. Hardware flow control is not
00038  * implemented yet. This implementation is just so some application can use
00039  * the pins, it would also be possible for rs232.c to use it for hardware
00040  * handshake but as said, that is not implemented yet.
00041  */
00042 
00043 #include "dev/ctsrts-sensor.h"
00044 #include "dev/irq.h"
00045 #include "dev/hwconf.h"
00046 
00047 const struct sensors_sensor ctsrts_sensor;
00048 
00049 HWCONF_PIN(RS232RTS, 1, 7);
00050 
00051 #define RS232CTS_IRQ() 6
00052 HWCONF_PIN(RS232CTS, 1, RS232CTS_IRQ());
00053 HWCONF_IRQ(RS232CTS, 1, RS232CTS_IRQ());
00054 
00055 /*---------------------------------------------------------------------------*/
00056 static int
00057 irq(void)
00058 {
00059   /* Change the flank triggering for the irq so we will detect next shift. */
00060   if(RS232CTS_READ()) {
00061     RS232CTS_IRQ_EDGE_SELECTD();
00062   } else {
00063     RS232CTS_IRQ_EDGE_SELECTU();
00064   }
00065   sensors_changed(&ctsrts_sensor);
00066   return 1;
00067 }
00068 /*---------------------------------------------------------------------------*/
00069 static int
00070 value(int type)
00071 {
00072   /*
00073    * Invert the bit and return.
00074    * This is strange, accordingly to the MSP430 manual section 9.2.1, Input
00075    * Register PxIN the bit should be low when input is low. In RealTerm on
00076    * the PC I set RTS which is coupled to the CTS on the esb and I read a 0.
00077    * Maybe RTS is defined active LOW on the PC? //Kalle
00078    */
00079   return RS232CTS_READ() ? 0 : 1;
00080 }
00081 /*---------------------------------------------------------------------------*/
00082 static int
00083 configure(int type, int value)
00084 {
00085   switch(type) {
00086   case SENSORS_HW_INIT:
00087     RS232RTS_SELECT();
00088     RS232RTS_MAKE_OUTPUT();
00089     RS232RTS_CLEAR();
00090     RS232CTS_SELECT();
00091     RS232CTS_MAKE_INPUT();
00092     return 1;
00093   case SENSORS_ACTIVE:
00094     if(value) {
00095       if(!RS232CTS_IRQ_ENABLED()) {
00096 
00097         /*
00098          * Check current status on the CTS pin and set IRQ flank so we
00099          * will detect a shift.
00100          */
00101         if(RS232CTS_READ()) {
00102           RS232CTS_IRQ_EDGE_SELECTD();
00103         } else {
00104           RS232CTS_IRQ_EDGE_SELECTU();
00105         }
00106 
00107         irq_port1_activate(RS232CTS_IRQ(), irq);
00108         RS232CTS_ENABLE_IRQ();
00109       }
00110     } else {
00111       RS232CTS_DISABLE_IRQ();
00112       irq_port1_deactivate(RS232CTS_IRQ());
00113     }
00114     return 1;
00115   }
00116   return 0;
00117 }
00118 /*---------------------------------------------------------------------------*/
00119 static int
00120 status(int type)
00121 {
00122   switch(type) {
00123   case SENSORS_ACTIVE:
00124   case SENSORS_READY:
00125     return RS232CTS_IRQ_ENABLED();
00126   }
00127   return 0;
00128 }
00129 /*---------------------------------------------------------------------------*/
00130 /**
00131  * Indicate to host/client we are NOT ready to receive data. Sets the RTS pin
00132  * to low.
00133  */
00134 void ctsrts_rts_clear(void) {
00135   RS232RTS_CLEAR();
00136 }
00137 /*---------------------------------------------------------------------------*/
00138 /**
00139  * Request host/client to send data. Sets the RTS pin to high.
00140  */
00141 void ctsrts_rts_set(void) {
00142   RS232RTS_SET();
00143 }
00144 /*---------------------------------------------------------------------------*/
00145 SENSORS_SENSOR(ctsrts_sensor, CTSRTS_SENSOR,
00146                value, configure, status);