radiotimingc.nc

传感器网络中的嵌入式操作系统源代码

// $Id: RadioTimingC.nc,v 1.3.4.2 2003/08/18 22:09:49 cssharp Exp $

/*									tab:4
 * "Copyright (c) 2000-2003 The Regents of the University  of California.  
 * All rights reserved.
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 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice, the following
 * two paragraphs and the author appear in all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
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 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
 *
 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE     
 * file. If you do not find these files, copies can be found by writing to
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
 * 94704.  Attention:  Intel License Inquiry.
 */
/*
 *
 */
module RadioTimingC {
  provides interface RadioTiming;
}

implementation {

  async command uint16_t RadioTiming.getTiming() {
    //enable input capture.
    //	
    cbi(DDRB, 4);
    while(TOSH_READ_RFM_RXD_PIN()) { }
    outp(0x41, TCCR1B);
    //clear capture flag
    outp(0x1<<ICF1, TIFR);
    //wait for the capture.
    while((inp(TIFR) & (0x1 << ICF1)) == 0) { }
    sbi(PORTB, 6);
    cbi(PORTB, 6);
    return __inw_atomic(ICR1L);
  }
  
  async command uint16_t RadioTiming.currentTime() {
    return __inw_atomic(TCNT1L);
  }
}