Contiki-NG
cc2520-arch-sfd.c
1 /*
2  * Copyright (c) 2011, 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 #include "contiki.h"
31 #include "dev/spi-legacy.h"
32 #include "dev/cc2520/cc2520.h"
33 #include "isr_compat.h"
34 
35 extern volatile uint8_t cc2520_sfd_counter;
36 extern volatile uint16_t cc2520_sfd_start_time;
37 extern volatile uint16_t cc2520_sfd_end_time;
38 
39 /*---------------------------------------------------------------------------*/
40 /* SFD interrupt for timestamping radio packets */
41 ISR(TIMERB1, cc2520_timerb1_interrupt)
42 {
43  int tbiv;
44 
45  /* always read TBIV to clear IFG */
46  tbiv = TBIV;
47  /* read and discard tbiv to avoid "variable set but not used" warning */
48  (void)tbiv;
49  if(CC2520_SFD_IS_1) {
50  cc2520_sfd_counter++;
51  cc2520_sfd_start_time = TBCCR1;
52  } else {
53  cc2520_sfd_counter = 0;
54  cc2520_sfd_end_time = TBCCR1;
55  }
56 }
57 /*---------------------------------------------------------------------------*/
58 void
59 cc2520_arch_sfd_init(void)
60 {
61  /* Need to select the special function! */
62  CC2520_SFD_PORT(SEL) = BV(CC2520_SFD_PIN);
63 
64  /* start timer B - 32768 ticks per second */
65  TBCTL = TBSSEL_1 | TBCLR;
66 
67  /* CM_3 = capture mode - capture on both edges */
68  TBCCTL1 = CM_3 | CAP | SCS;
69  TBCCTL1 |= CCIE;
70 
71  /* Start Timer_B in continuous mode. */
72  TBCTL |= MC1;
73 
74  TBR = RTIMER_NOW();
75 }
76 /*---------------------------------------------------------------------------*/
#define RTIMER_NOW()
Get the current clock time.
Definition: rtimer.h:185
Basic SPI macros