sht11-sensor.c

00001 /*
00002  * Copyright (c) 2005, Swedish Institute of Computer Science
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the Institute nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  *
00029  * This file is part of the Contiki operating system.
00030  *
00031  * @(#)$Id: sht11-sensor.c,v 1.2 2010/01/15 08:51:21 adamdunkels Exp $
00032  */
00033 
00034 #include <stdlib.h>
00035 
00036 #include <io.h>
00037 
00038 #include "contiki.h"
00039 #include "lib/sensors.h"
00040 #include "dev/sht11.h"
00041 #include "dev/sht11-sensor.h"
00042 
00043 const struct sensors_sensor sht11_sensor;
00044 
00045 enum {
00046   ON, OFF
00047 };
00048 static uint8_t state = OFF;
00049 
00050 /*---------------------------------------------------------------------------*/
00051 static int
00052 value(int type)
00053 {
00054   switch(type) {
00055     /* Photosynthetically Active Radiation. */
00056   case SHT11_SENSOR_TEMP:
00057     return sht11_temp();;
00058 
00059     /* Total Solar Radiation. */
00060   case SHT11_SENSOR_HUMIDITY:
00061     return sht11_humidity();
00062 
00063   case SHT11_SENSOR_BATTERY_INDICATOR:
00064     return sht11_sreg() & 0x40? 1: 0;
00065 }
00066   return 0;
00067 }
00068 /*---------------------------------------------------------------------------*/
00069 static int
00070 status(int type)
00071 {
00072   switch(type) {
00073   case SENSORS_ACTIVE:
00074   case SENSORS_READY:
00075     return (state == ON);
00076   }
00077   return 0;
00078 }
00079 
00080 /*---------------------------------------------------------------------------*/
00081 static int
00082 configure(int type, int c)
00083 {
00084   switch(type) {
00085   case SENSORS_ACTIVE:
00086     if(c) {
00087       if(!status(SENSORS_ACTIVE)) {
00088         rtimer_clock_t t0;
00089         sht11_init();
00090         state = ON;
00091 
00092         /* For for about 11 ms before the SHT11 can be used. */
00093         t0 = RTIMER_NOW();
00094         while(RTIMER_CLOCK_LT(RTIMER_NOW(), t0 + RTIMER_SECOND / 100));
00095       }
00096     } else {
00097       sht11_off();
00098       state = OFF;
00099     }
00100   }
00101   return 0;
00102 }
00103 /*---------------------------------------------------------------------------*/
00104 SENSORS_SENSOR(sht11_sensor, "sht11",
00105                value, configure, status);

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