cpu/msp430/button.c

   1 /*
   2  * Copyright (c) 2006, 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: button.c,v 1.2 2006/08/17 15:41:13 bg- Exp $
  30  */
  31
  32 #include <io.h>
  33 #include <signal.h>
  34
  35 #include "contiki.h"
  36
  37 #include "dev/button.h"
  38
  39 #define BUTTON_PORT 2
  40 #define BUTTON_PIN  7
  41
  42 static struct button_msg button_msg;
  43
  44 static struct process *selecting_proc;
  45
  46 void
  47 button_init(struct process *proc)
  48 {
  49   button_msg.type = BUTTON_MSG_TYPE;
  50
  51   P2DIR &= ~BV(BUTTON_PIN);
  52   P2SEL &= ~BV(BUTTON_PIN);
  53
  54   P2IES |= BV(BUTTON_PIN);
  55   P2IFG &= ~BV(BUTTON_PIN);
  56
  57   selecting_proc = proc;
  58   if(proc != NULL)
  59     P2IE |= BV(BUTTON_PIN);
  60   else
  61     P2IE &= ~BV(BUTTON_PIN);
  62 }
  63
  64 interrupt(PORT2_VECTOR)
  65 __button_interrupt(void)
  66 {
  67   static struct timer debouncetimer;
  68
  69   P2IFG &= ~BV(BUTTON_PIN);
  70   if(timer_expired(&debouncetimer)) {
  71     button_msg.value = P2IN & BV(BUTTON_PIN);
  72     timer_set(&debouncetimer, CLOCK_SECOND/4);
  73     if(selecting_proc != NULL) {
  74       process_post(selecting_proc, PROCESS_EVENT_MSG, &button_msg);
  75     }
  76     LPM4_EXIT;
  77   }
  78 }