Contiki-NG
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  */
30 
31 #include "contiki.h"
32 #include "dev/spi-legacy.h"
33 #include "cc2420.h"
34 #include "isr_compat.h"
35 
36 extern volatile uint8_t cc2420_sfd_counter;
37 extern volatile uint16_t cc2420_sfd_start_time;
38 extern volatile uint16_t cc2420_sfd_end_time;
39 
40 /*---------------------------------------------------------------------------*/
41 /* SFD interrupt for timestamping radio packets */
42 ISR(TIMERB1, cc2420_timerb1_interrupt)
43 {
44  int tbiv;
45 
46  /* always read TBIV to clear IFG */
47  tbiv = TBIV;
48  /* read and discard tbiv to avoid "variable set but not used" warning */
49  (void)tbiv;
50  if(CC2420_SFD_IS_1) {
51  cc2420_sfd_counter++;
52  cc2420_sfd_start_time = TBCCR1;
53  } else {
54  cc2420_sfd_counter = 0;
55  cc2420_sfd_end_time = TBCCR1;
56  }
57 }
58 /*---------------------------------------------------------------------------*/
59 void
60 cc2420_arch_sfd_init(void)
61 {
62  /* Need to select the special function! */
63  CC2420_SFD_PORT(SEL) = BV(CC2420_SFD_PIN);
64 
65  /* start timer B - 32768 ticks per second */
66  TBCTL = TBSSEL_1 | TBCLR;
67 
68  /* CM_3 = capture mode - capture on both edges */
69  TBCCTL1 = CM_3 | CAP | SCS;
70  TBCCTL1 |= CCIE;
71 
72  /* Start Timer_B in continuous mode. */
73  TBCTL |= MC1;
74 
75  TBR = RTIMER_NOW();
76 }
77 /*---------------------------------------------------------------------------*/
CC2420 driver header file
#define RTIMER_NOW()
Get the current clock time.
Definition: rtimer.h:160
Basic SPI macros