00001 /* 00002 * Copyright (C) 2006 by egnite Software GmbH. All rights reserved. 00003 * 00004 * Redistribution and use in source and binary forms, with or without 00005 * modification, are permitted provided that the following conditions 00006 * are met: 00007 * 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 copyright holders nor the names of 00014 * contributors may be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS 00018 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00019 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00020 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE 00021 * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00022 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00023 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00024 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00025 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00026 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 00027 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * For additional information see http://www.ethernut.de/ 00031 * 00032 */ 00033 00034 /* 00035 * $Log: wdt_avr.c,v $ 00036 * Revision 1.1 2006/05/25 09:13:23 haraldkipp 00037 * Platform independent watchdog API added. 00038 * 00039 */ 00040 00041 #if defined(__GNUC__) 00042 #include <avr/wdt.h> 00043 #endif 00044 #include <sys/timer.h> 00045 #include <dev/watchdog.h> 00046 00051 00055 #ifndef NUT_WDT_FREQ 00056 #define NUT_WDT_FREQ 1165000 00057 #endif 00058 00059 static ureg_t nested; 00060 static u_char wdt_div; 00061 00062 00073 u_long AvrWatchDogStart(u_long ms) 00074 { 00075 u_long ticks; 00076 00077 wdt_reset(); 00078 00079 ticks = ((NUT_WDT_FREQ / 1000UL) * ms) >> 14; 00080 for (wdt_div = 0; wdt_div < 7 && ticks; wdt_div++) { 00081 ticks >>= 1; 00082 } 00083 wdt_enable(wdt_div); 00084 00085 nested = 1; 00086 00087 return (16384UL << wdt_div) / (NUT_WDT_FREQ / 1000UL); 00088 } 00089 00096 void AvrWatchDogRestart(void) 00097 { 00098 wdt_reset(); 00099 } 00100 00107 void AvrWatchDogDisable(void) 00108 { 00109 if (nested) { 00110 nested++; 00111 } 00112 wdt_disable(); 00113 } 00114 00121 void AvrWatchDogEnable(void) 00122 { 00123 if (nested > 1 && --nested == 1) { 00124 wdt_enable(wdt_div); 00125 } 00126 } 00127