159 lines
		
	
	
	
		
			5.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			159 lines
		
	
	
	
		
			5.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* This is from http://www.mtcnet.net/~henryvm/wdt/ */
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| #ifndef _AVR_WD_H_
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| #define _AVR_WD_H_
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| 
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| #include <avr/io.h>
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| 
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| /*
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| Copyright (c) 2009, Curt Van Maanen
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| 
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| Permission to use, copy, modify, and/or distribute this software for any
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| purpose with or without fee is hereby granted, provided that the above
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| copyright notice and this permission notice appear in all copies.
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| 
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| THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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| WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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| ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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| OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 
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| 
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| include usage-
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|     #include "wd.h"             //if in same directory as project
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|     #include <avr/wd.h>         //if wd.h is in avr directory
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| 
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| set watchdog modes and prescale
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| 
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| usage-
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|     WD_SET(mode,[timeout]);     //prescale always set
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| 
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| modes-
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|     WD_OFF                      disabled
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|     WD_RST                      normal reset mode
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|     WD_IRQ                      interrupt only mode (if supported)
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|     WD_RST_IRQ                  interrupt+reset mode (if supported)
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| 
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| timeout-
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|     WDTO_15MS                   default if no timeout provided
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|     WDTO_30MS
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|     WDTO_60MS
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|     WDTO_120MS
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|     WDTO_250MS
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|     WDTO_500MS
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|     WDTO_1S
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|     WDTO_2S
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|     WDTO_4S                     (if supported)
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|     WDTO_8S                     (if supported)
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| 
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| examples-
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|     WD_SET(WD_RST,WDTO_1S);     //reset mode, 1s timeout
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|     WD_SET(WD_OFF);             //watchdog disabled (if not fused on)
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|     WD_SET(WD_RST);             //reset mode, 15ms (default timeout)
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|     WD_SET(WD_IRQ,WDTO_120MS);  //interrupt only mode, 120ms timeout
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|     WD_SET(WD_RST_IRQ,WDTO_2S); //interrupt+reset mode, 2S timeout
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| 
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| 
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| for enhanced watchdogs, if the watchdog is not being used WDRF should be
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| cleared on every power up or reset, along with disabling the watchdog-
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|     WD_DISABLE();               //clear WDRF, then turn off watchdog
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| 
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| */
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| 
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| //reset registers to the same name (MCUCSR)
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| #if !defined(MCUCSR)
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| #define MCUCSR                  MCUSR
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| #endif
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| 
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| //watchdog registers to the same name (WDTCSR)
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| #if !defined(WDTCSR)
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| #define WDTCSR                  WDTCR
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| #endif
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| 
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| //if enhanced watchdog, define irq values, create disable macro
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| #if defined(WDIF)
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| #define WD_IRQ                  0xC0
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| #define WD_RST_IRQ              0xC8
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| #define WD_DISABLE()            do{                       \
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|                                     MCUCSR &= ~(1<<WDRF); \
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|                                     WD_SET(WD_OFF);       \
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|                                 }while(0)
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| #endif
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| 
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| //all watchdogs
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| #define WD_RST                  8
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| #define WD_OFF                  0
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| 
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| //prescale values
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| #define WDTO_15MS               0
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| #define WDTO_30MS               1
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| #define WDTO_60MS               2
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| #define WDTO_120MS              3
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| #define WDTO_250MS              4
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| #define WDTO_500MS              5
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| #define WDTO_1S                 6
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| #define WDTO_2S                 7
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| 
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| //prescale values for avrs with WDP3
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| #if defined(WDP3)
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| #define WDTO_4S                 0x20
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| #define WDTO_8S                 0x21
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| #endif
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| 
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| //watchdog reset
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| #define WDR()                   __asm__ __volatile__("wdr")
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| 
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| //avr reset using watchdog
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| #define WD_AVR_RESET()          do{                              \
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|                                     __asm__ __volatile__("cli"); \
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|                                     WD_SET_UNSAFE(WD_RST);       \
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|                                     while(1);                    \
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|                                 }while(0)
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| 
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| /*set the watchdog-
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| 1. save SREG
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| 2. turn off irq's
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| 3. reset watchdog timer
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| 4. enable watchdog change
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| 5. write watchdog value
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| 6. restore SREG (restoring irq status)
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| */
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| #define WD_SET(val,...)                                 \
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|     __asm__ __volatile__(                               \
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|         "in __tmp_reg__,__SREG__"           "\n\t"      \
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|         "cli"                               "\n\t"      \
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|         "wdr"                               "\n\t"      \
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|         "sts %[wdreg],%[wden]"              "\n\t"      \
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|         "sts %[wdreg],%[wdval]"             "\n\t"      \
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|         "out __SREG__,__tmp_reg__"          "\n\t"      \
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|         :                                               \
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|         : [wdreg] "M" (&WDTCSR),                        \
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|           [wden]  "r" ((uint8_t)(0x18)),                \
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|           [wdval] "r" ((uint8_t)(val|(__VA_ARGS__+0)))  \
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|         : "r0"                                          \
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| )
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| 
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| /*set the watchdog when I bit in SREG known to be clear-
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| 1. reset watchdog timer
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| 2. enable watchdog change
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| 5. write watchdog value
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| */
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| #define WD_SET_UNSAFE(val,...)                          \
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|     __asm__ __volatile__(                               \
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|         "wdr"                               "\n\t"      \
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|         "sts %[wdreg],%[wden]"              "\n\t"      \
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|         "sts %[wdreg],%[wdval]"             "\n\t"      \
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|         :                                               \
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|         : [wdreg] "M" (&WDTCSR),                        \
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|           [wden]  "r" ((uint8_t)(0x18)),                \
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|           [wdval] "r" ((uint8_t)(val|(__VA_ARGS__+0)))  \
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| )
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| 
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| 
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| //for compatibility with avr/wdt.h
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| #define wdt_enable(val) WD_SET(WD_RST,val)
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| #define wdt_disable()   WD_SET(WD_OFF)
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| 
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| 
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| #endif /* _AVR_WD_H_ */
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