timer_avr.h

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/*#*
 *#* $Log$
 *#* Revision 1.32  2007/10/08 12:14:32  batt
 *#* Fix some review issues.
 *#*
 *#* Revision 1.31  2007/10/07 12:30:55  batt
 *#* Add default timer for AVR.
 *#*
 *#* Revision 1.30  2007/06/07 14:35:12  batt
 *#* Merge from project_ks.
 *#*
 *#* Revision 1.29  2007/03/21 11:01:36  batt
 *#* Add missing support for ATMega1281.
 *#*
 *#* Revision 1.28  2006/07/19 12:56:26  bernie
 *#* Convert to new Doxygen style.
 *#*
 *#* Revision 1.27  2006/05/18 00:38:24  bernie
 *#* Use hw_cpu.h instead of ubiquitous hw.h.
 *#*
 *#* Revision 1.26  2006/02/21 21:28:02  bernie
 *#* New time handling based on TIMER_TICKS_PER_SEC to support slow timers with ticks longer than 1ms.
 *#*
 *#* Revision 1.25  2005/07/19 07:26:37  bernie
 *#* Refactor to decouple timer ticks from milliseconds.
 *#*
 *#* Revision 1.24  2005/04/11 19:10:28  bernie
 *#* Include top-level headers from cfg/ subdir.
 *#*
 *#* Revision 1.23  2005/03/01 23:24:51  bernie
 *#* Tweaks for avr-libc 1.2.x.
 *#*
 *#* Revision 1.21  2004/12/13 12:07:06  bernie
 *#* DISABLE_IRQSAVE/ENABLE_IRQRESTORE: Convert to IRQ_SAVE_DISABLE/IRQ_RESTORE.
 *#*
 *#* Revision 1.20  2004/11/16 20:59:46  bernie
 *#* Include <avr/io.h> explicitly.
 *#*
 *#* Revision 1.19  2004/10/19 08:56:41  bernie
 *#* TIMER_STROBE_ON, TIMER_STROBE_OFF, TIMER_STROBE_INIT: Move from timer_avr.h to timer.h, where they really belong.
 *#*
 *#* Revision 1.18  2004/09/20 03:31:03  bernie
 *#* Fix racy racy code.
 *#*/
#ifndef DRV_TIMER_AVR_H
#define DRV_TIMER_AVR_H

#include <appconfig.h>     /* CONFIG_TIMER */
#include <cfg/compiler.h>  /* uint8_t */
#include <cfg/macros.h>    /* DIV_ROUND */
#include <hw_cpu.h>        /* CLOCK_FREQ */

#define TIMER_ON_OUTPUT_COMPARE0  1
#define TIMER_ON_OVERFLOW1        2
#define TIMER_ON_OUTPUT_COMPARE2  3
#define TIMER_ON_OVERFLOW3        4

#define TIMER_DEFAULT TIMER_ON_OUTPUT_COMPARE0 
/* \} */

/*
 * Hardware dependent timer initialization.
 */
#if (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE0)

    #define TIMER_PRESCALER      64
    #define TIMER_HW_BITS        8
    #define DEFINE_TIMER_ISR     SIGNAL(SIG_OUTPUT_COMPARE0)
    #define TIMER_TICKS_PER_SEC  1000
    #define TIMER_HW_CNT         OCR_DIVISOR

    typedef uint8_t hptime_t;

#elif (CONFIG_TIMER == TIMER_ON_OVERFLOW1)

    #define TIMER_PRESCALER      1
    #define TIMER_HW_BITS        8

    #define TIMER_HW_CNT         (1 << TIMER_HW_BITS)
    #define DEFINE_TIMER_ISR     SIGNAL(SIG_OVERFLOW1)
    #define TIMER_TICKS_PER_SEC  DIV_ROUND(TIMER_HW_HPTICKS_PER_SEC, TIMER_HW_CNT)

    typedef uint16_t hptime_t;

#elif (CONFIG_TIMER == TIMER_ON_OUTPUT_COMPARE2)

    #define TIMER_PRESCALER      64
    #define TIMER_HW_BITS        8
    #if CPU_AVR_ATMEGA1281 || CPU_AVR_ATMEGA168
        #define DEFINE_TIMER_ISR     SIGNAL(SIG_OUTPUT_COMPARE2A)
    #else
        #define DEFINE_TIMER_ISR     SIGNAL(SIG_OUTPUT_COMPARE2)
    #endif
    #define TIMER_TICKS_PER_SEC  1000

    #define TIMER_HW_CNT         OCR_DIVISOR


    typedef uint8_t hptime_t;

#elif (CONFIG_TIMER == TIMER_ON_OVERFLOW3)

    #define TIMER_PRESCALER      1
    #define TIMER_HW_BITS        8

    #define TIMER_HW_CNT         (1 << TIMER_HW_BITS)
    #define DEFINE_TIMER_ISR     SIGNAL(SIG_OVERFLOW3)
    #define TIMER_TICKS_PER_SEC  DIV_ROUND(TIMER_HW_HPTICKS_PER_SEC, TIMER_HW_CNT)

    typedef uint16_t hptime_t;
#else

    #error Unimplemented value for CONFIG_TIMER
#endif /* CONFIG_TIMER */


#define TIMER_HW_HPTICKS_PER_SEC  DIV_ROUND(CLOCK_FREQ, TIMER_PRESCALER)

#define OCR_DIVISOR  (DIV_ROUND(DIV_ROUND(CLOCK_FREQ, TIMER_PRESCALER), TIMER_TICKS_PER_SEC) - 1)

#define timer_hw_irq() do {} while (0)

#define timer_hw_triggered() (true)


#endif /* DRV_TIMER_AVR_H */