cpu/msp430/cc2420-arch-sfd.c

   1 /*
   2  * Copyright (c) 2009, Swedish Institute of Computer Science
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the Institute nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)$Id: cc2420-arch-sfd.c,v 1.3 2010/01/26 10:20:16 adamdunkels Exp $
  30  */
  31
  32 #include <io.h>
  33 #include <signal.h>
  34
  35 #include "dev/spi.h"
  36 #include "dev/cc2420.h"
  37
  38 volatile uint8_t cc2420_arch_sfd_counter;
  39 volatile uint16_t cc2420_arch_sfd_start_time;
  40 volatile uint16_t cc2420_arch_sfd_end_time;
  41
  42 /*---------------------------------------------------------------------------*/
  43 /* SFD interrupt for timestamping radio packets */
  44 interrupt(TIMERB1_VECTOR)
  45 cc24240_timerb1_interrupt(void)
  46 {
  47   int tbiv;
  48   ENERGEST_ON(ENERGEST_TYPE_IRQ);
  49   /* always read TBIV to clear IFG */
  50   tbiv = TBIV;
  51   if(SFD_IS_1) {
  52     cc2420_arch_sfd_counter++;
  53     cc2420_arch_sfd_start_time = TBCCR1;
  54   } else {
  55     cc2420_arch_sfd_counter = 0;
  56     cc2420_arch_sfd_end_time = TBCCR1;
  57   }
  58   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
  59 }
  60 /*---------------------------------------------------------------------------*/
  61 void
  62 cc2420_arch_sfd_init(void)
  63 {
  64   /* Need to select the special function! */
  65   P4SEL = BV(SFD);
  66
  67   /* start timer B - 32768 ticks per second */
  68   TBCTL = TBSSEL_1 | TBCLR;
  69
  70   /* CM_3 = capture mode - capture on both edges */
  71   TBCCTL1 = CM_3 | CAP | SCS;
  72   TBCCTL1 |= CCIE;
  73
  74   /* Start Timer_B in continuous mode. */
  75   TBCTL |= MC1;
  76 }
  77 /*---------------------------------------------------------------------------*/