protocol/iwrap/wd.h

   1 /* This is from http://www.mtcnet.net/~henryvm/wdt/ */
   2 #ifndef _AVR_WD_H_
   3 #define _AVR_WD_H_
   4
   5 #include <avr/io.h>
   6
   7 /*
   8 Copyright (c) 2009, Curt Van Maanen
   9
  10 Permission to use, copy, modify, and/or distribute this software for any
  11 purpose with or without fee is hereby granted, provided that the above
  12 copyright notice and this permission notice appear in all copies.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  15 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  16 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  17 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  18 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  19 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  20 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  21
  22
  23 include usage-
  24     #include "wd.h"             //if in same directory as project
  25     #include <avr/wd.h>         //if wd.h is in avr directory
  26
  27 set watchdog modes and prescale
  28
  29 usage-
  30     WD_SET(mode,[timeout]);     //prescale always set
  31
  32 modes-
  33     WD_OFF                      disabled
  34     WD_RST                      normal reset mode
  35     WD_IRQ                      interrupt only mode (if supported)
  36     WD_RST_IRQ                  interrupt+reset mode (if supported)
  37
  38 timeout-
  39     WDTO_15MS                   default if no timeout provided
  40     WDTO_30MS
  41     WDTO_60MS
  42     WDTO_120MS
  43     WDTO_250MS
  44     WDTO_500MS
  45     WDTO_1S
  46     WDTO_2S
  47     WDTO_4S                     (if supported)
  48     WDTO_8S                     (if supported)
  49
  50 examples-
  51     WD_SET(WD_RST,WDTO_1S);     //reset mode, 1s timeout
  52     WD_SET(WD_OFF);             //watchdog disabled (if not fused on)
  53     WD_SET(WD_RST);             //reset mode, 15ms (default timeout)
  54     WD_SET(WD_IRQ,WDTO_120MS);  //interrupt only mode, 120ms timeout
  55     WD_SET(WD_RST_IRQ,WDTO_2S); //interrupt+reset mode, 2S timeout
  56
  57
  58 for enhanced watchdogs, if the watchdog is not being used WDRF should be
  59 cleared on every power up or reset, along with disabling the watchdog-
  60     WD_DISABLE();               //clear WDRF, then turn off watchdog
  61
  62 */
  63
  64 //reset registers to the same name (MCUCSR)
  65 #if !defined(MCUCSR)
  66 #define MCUCSR                  MCUSR
  67 #endif
  68
  69 //watchdog registers to the same name (WDTCSR)
  70 #if !defined(WDTCSR)
  71 #define WDTCSR                  WDTCR
  72 #endif
  73
  74 //if enhanced watchdog, define irq values, create disable macro
  75 #if defined(WDIF)
  76 #define WD_IRQ                  0xC0
  77 #define WD_RST_IRQ              0xC8
  78 #define WD_DISABLE()            do{                       \
  79                                     MCUCSR &= ~(1<<WDRF); \
  80                                     WD_SET(WD_OFF);       \
  81                                 }while(0)
  82 #endif
  83
  84 //all watchdogs
  85 #define WD_RST                  8
  86 #define WD_OFF                  0
  87
  88 //prescale values
  89 #define WDTO_15MS               0
  90 #define WDTO_30MS               1
  91 #define WDTO_60MS               2
  92 #define WDTO_120MS              3
  93 #define WDTO_250MS              4
  94 #define WDTO_500MS              5
  95 #define WDTO_1S                 6
  96 #define WDTO_2S                 7
  97
  98 //prescale values for avrs with WDP3
  99 #if defined(WDP3)
 100 #define WDTO_4S                 0x20
 101 #define WDTO_8S                 0x21
 102 #endif
 103
 104 //watchdog reset
 105 #define WDR()                   __asm__ __volatile__("wdr")
 106
 107 //avr reset using watchdog
 108 #define WD_AVR_RESET()          do{                              \
 109                                     __asm__ __volatile__("cli"); \
 110                                     WD_SET_UNSAFE(WD_RST);       \
 111                                     while(1);                    \
 112                                 }while(0)
 113
 114 /*set the watchdog-
 115 1. save SREG
 116 2. turn off irq's
 117 3. reset watchdog timer
 118 4. enable watchdog change
 119 5. write watchdog value
 120 6. restore SREG (restoring irq status)
 121 */
 122 #define WD_SET(val,...)                                 \
 123     __asm__ __volatile__(                               \
 124         "in __tmp_reg__,__SREG__"           "\n\t"      \
 125         "cli"                               "\n\t"      \
 126         "wdr"                               "\n\t"      \
 127         "sts %[wdreg],%[wden]"              "\n\t"      \
 128         "sts %[wdreg],%[wdval]"             "\n\t"      \
 129         "out __SREG__,__tmp_reg__"          "\n\t"      \
 130         :                                               \
 131         : [wdreg] "M" (&WDTCSR),                        \
 132           [wden]  "r" ((uint8_t)(0x18)),                \
 133           [wdval] "r" ((uint8_t)(val|(__VA_ARGS__+0)))  \
 134         : "r0"                                          \
 135 )
 136
 137 /*set the watchdog when I bit in SREG known to be clear-
 138 1. reset watchdog timer
 139 2. enable watchdog change
 140 5. write watchdog value
 141 */
 142 #define WD_SET_UNSAFE(val,...)                          \
 143     __asm__ __volatile__(                               \
 144         "wdr"                               "\n\t"      \
 145         "sts %[wdreg],%[wden]"              "\n\t"      \
 146         "sts %[wdreg],%[wdval]"             "\n\t"      \
 147         :                                               \
 148         : [wdreg] "M" (&WDTCSR),                        \
 149           [wden]  "r" ((uint8_t)(0x18)),                \
 150           [wdval] "r" ((uint8_t)(val|(__VA_ARGS__+0)))  \
 151 )
 152
 153
 154 //for compatibility with avr/wdt.h
 155 #define wdt_enable(val) WD_SET(WD_RST,val)
 156 #define wdt_disable()   WD_SET(WD_OFF)
 157
 158
 159 #endif /* _AVR_WD_H_ */