text: /*
   * Copyright (c) 2005, Swedish Institute of Computer Science
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * This file is part of the Contiki operating system.
   *
   * @(#)$Id: ctsrts-sensor.c,v 1.4 2010/02/08 00:00:45 nifi Exp $
   */
  
  /**
   * RTS/CTS (Request to Send/Clear to Send) are the signals used for hardware
   * flow control. By setting the RTS line to "ON" the host tells the connected
   * device that it is ready to receive data. Hardware flow control is not
   * implemented yet. This implementation is just so some application can use
   * the pins, it would also be possible for rs232.c to use it for hardware
   * handshake but as said, that is not implemented yet.
   */
  
  #include "dev/ctsrts-sensor.h"
  #include "dev/irq.h"
  #include "dev/hwconf.h"
  #include <signal.h>
  
  const struct sensors_sensor ctsrts_sensor;
  
  HWCONF_PIN(RS232RTS, 1, 7);
  
  #define RS232CTS_IRQ() 6
  HWCONF_PIN(RS232CTS, 1, RS232CTS_IRQ());
  HWCONF_IRQ(RS232CTS, 1, RS232CTS_IRQ());
  
  /*---------------------------------------------------------------------------*/
  static int
  irq(void)
  {
    /* Change the flank triggering for the irq so we will detect next shift. */
    if(RS232CTS_READ()) {
      RS232CTS_IRQ_EDGE_SELECTD();
    } else {
      RS232CTS_IRQ_EDGE_SELECTU();
    }
    sensors_changed(&ctsrts_sensor);
    return 1;
  }
  /*---------------------------------------------------------------------------*/
  static int
  value(int type)
  {
    /*
     * Invert the bit and return.
     * This is strange, accordingly to the MSP430 manual section 9.2.1, Input
     * Register PxIN the bit should be low when input is low. In RealTerm on
     * the PC I set RTS which is coupled to the CTS on the esb and I read a 0.
     * Maybe RTS is defined active LOW on the PC? //Kalle
     */
    return RS232CTS_READ() ? 0 : 1;
  }
  /*---------------------------------------------------------------------------*/
  static int
  configure(int type, int value)
  {
    switch(type) {
    case SENSORS_HW_INIT:
      RS232RTS_SELECT();
      RS232RTS_MAKE_OUTPUT();
      RS232RTS_CLEAR();
      RS232CTS_SELECT();
      RS232CTS_MAKE_INPUT();
      return 1;
    case SENSORS_ACTIVE:
      if(value) {
        if(!RS232CTS_IRQ_ENABLED()) {
  
          /*
           * Check current status on the CTS pin and set IRQ flank so we
           * will detect a shift.
           */
          if(RS232CTS_READ()) {
            RS232CTS_IRQ_EDGE_SELECTD();
          } else {
            RS232CTS_IRQ_EDGE_SELECTU();
          }
  
          irq_port1_activate(RS232CTS_IRQ(), irq);
          RS232CTS_ENABLE_IRQ();
        }
      } else {
        RS232CTS_DISABLE_IRQ();
        irq_port1_deactivate(RS232CTS_IRQ());
      }
      return 1;
    }
    return 0;
  }
  /*---------------------------------------------------------------------------*/
  static int
  status(int type)
  {
    switch(type) {
    case SENSORS_ACTIVE:
    case SENSORS_READY:
      return RS232CTS_IRQ_ENABLED();
    }
    return 0;
  }
  /*---------------------------------------------------------------------------*/
  /**
   * Indicate to host/client we are NOT ready to receive data. Sets the RTS pin
   * to low.
   */
  void ctsrts_rts_clear(void) {
    RS232RTS_CLEAR();
  }
  /*---------------------------------------------------------------------------*/
  /**
   * Request host/client to send data. Sets the RTS pin to high.
   */
  void ctsrts_rts_set(void) {
    RS232RTS_SET();
  }
  /*---------------------------------------------------------------------------*/
  SENSORS_SENSOR(ctsrts_sensor, CTSRTS_SENSOR,
                 value, configure, status);
  