timer_dsp56k.h

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#error This code must be revised for the new timer API

/*#*
 *#* $Log$
 *#* Revision 1.10  2006/07/19 12:56:26  bernie
 *#* Convert to new Doxygen style.
 *#*
 *#* Revision 1.9  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 1.8  2005/11/04 16:20:02  bernie
 *#* Fix reference to README.devlib in header.
 *#*
 *#* Revision 1.7  2005/04/11 19:10:28  bernie
 *#* Include top-level headers from cfg/ subdir.
 *#*
 *#* Revision 1.6  2004/11/16 22:37:14  bernie
 *#* Replace IPTR with iptr_t.
 *#*
 *#* Revision 1.5  2004/08/25 14:12:08  rasky
 *#* Aggiornato il comment block dei log RCS
 *#*
 *#* Revision 1.4  2004/07/30 14:27:49  rasky
 *#* Aggiornati alcuni file DSP56k per la nuova libreria di IRQ management
 *#*
 *#* Revision 1.3  2004/06/06 18:30:34  bernie
 *#* Import DSP56800 changes from SC.
 *#*
 *#* Revision 1.2  2004/06/03 11:27:09  bernie
 *#* Add dual-license information.
 *#*
 *#* Revision 1.1  2004/05/23 18:23:30  bernie
 *#* Import drv/timer module.
 *#*
 *#*/

#ifndef DRV_TIMER_DSP56K_H
#define DRV_TIMER_DSP56K_H

#include "timer.h"
#include <DSP56F807.h>
#include <cfg/compiler.h>
#include <hw.h>
#include <drv/irq.h>

// Calculate register pointer and irq vector from hw.h setting
#define REG_SYSTEM_TIMER          PP_CAT(REG_TIMER_, SYSTEM_TIMER)
#define SYSTEM_TIMER_IRQ_VECTOR   PP_CAT(IRQ_TIMER_, SYSTEM_TIMER)

#define TIMER_PRESCALER           16

#define TIMER_HW_HPTICKS_PER_SEC           (IPBUS_FREQ / TIMER_PRESCALER)

typedef uint16_t hptime_t;

static void system_timer_isr(UNUSED(iptr_t, arg));

static void timer_hw_init(void)
{
    uint16_t compare;

    // Clear compare flag status and enable interrupt on compare
    REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
    REG_SYSTEM_TIMER->SCR |= REG_TIMER_SCR_TCFIE;

    // Calculate the compare value needed to generate an interrupt exactly
    //  TICKS_PER_SEC times each second (usually, every millisecond). Check that
    //  the calculation is accurate, otherwise there is a precision error
    // (probably the prescaler is too big or too small).
    compare = TIMER_HW_HPTICKS_PER_SEC / TICKS_PER_SEC;
    ASSERT((uint32_t)compare * TICKS_PER_SEC == IPBUS_FREQ / TIMER_PRESCALER);
    REG_SYSTEM_TIMER->CMP1 = compare;

    // The value for reload (at initializationa and after compare is met) is zero
    REG_SYSTEM_TIMER->LOAD = 0;

    // Set the interrupt handler and priority
    irq_install(SYSTEM_TIMER_IRQ_VECTOR, &system_timer_isr, NULL);
    irq_setpriority(SYSTEM_TIMER_IRQ_VECTOR, IRQ_PRIORITY_SYSTEM_TIMER);

    // Small preprocessor trick to generate the REG_TIMER_CTRL_PRIMARY_IPBYNN macro
    //  needed to set the prescaler
    #define REG_CONTROL_PRESCALER             PP_CAT(REG_TIMER_CTRL_PRIMARY_IPBY, TIMER_PRESCALER)

    // Setup the counter and start counting
    REG_SYSTEM_TIMER->CTRL =
        REG_TIMER_CTRL_MODE_RISING    |          // count rising edges (normal)
        REG_CONTROL_PRESCALER         |          // frequency (IPbus / TIMER_PRESCALER)
        REG_TIMER_CTRL_LENGTH;                   // up to CMP1, then reload
}

INLINE void timer_hw_irq(void)
{
    // Clear the overflow flag so that we are ready for another interrupt
    REG_SYSTEM_TIMER->SCR &= ~REG_TIMER_SCR_TCF;
}

INLINE hptime_t timer_hw_hpread(void)
{
    return REG_SYSTEM_TIMER->CNTR;
}

#define DEFINE_TIMER_ISR \
    static void system_timer_isr(UNUSED(iptr_t, arg))

#endif /* DRV_TIMER_DSP56_H */