/***************************************************************************
* arch/z80/src/ez80/ez80_timerisr.c
*
* Copyright (C) 2008, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
***************************************************************************/
/***************************************************************************
* Included Files
***************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <debug.h>
#include <arch/io.h>
#include <nuttx/arch.h>
#include "chip/chip.h"
#include "clock_internal.h"
#include "up_internal.h"
/***************************************************************************
* Definitions
***************************************************************************/
/***************************************************************************
* Private Types
***************************************************************************/
/***************************************************************************
* Private Functions
***************************************************************************/
/***************************************************************************
* Public Functions
***************************************************************************/
/***************************************************************************
* Function: up_timerisr
*
* Description:
* The timer ISR will perform a variety of services for various portions
* of the system.
*
***************************************************************************/
int up_timerisr(int irq, chipreg_t *regs)
{
volatile ubyte reg;
/* Read the appropropriate timer0 registr to clear the interrupt */
#ifdef _EZ80F91
reg = inp(EZ80_TMR0_IIR);
#else
/* _EZ80190, _EZ80L92, _EZ80F92, _EZ80F93 */
reg = inp(EZ80_TMR0_CTL);
#endif
/* Process timer interrupt */
sched_process_timer();
/* Architecture specific hook into the timer interrupt handler */
#ifdef CONFIG_ARCH_TIMERHOOK
up_timerhook();
#endif
return 0;
}
/***************************************************************************
* Function: up_timerinit
*
* Description:
* This function is called during start-up to initialize the timer
* interrupt.
*
***************************************************************************/
void up_timerinit(void)
{
uint16 reload;
ubyte reg;
/* Disable the timer */
outp(EZ80_TMR0_CTL, 0x00);
/* Attach system timer interrupts */
irq_attach(EZ80_IRQ_SYSTIMER, (xcpt_t)up_timerisr);
/* Set up the timer reload value */
/* Write to the timer reload register to set the reload value.
*
* In continuous mode:
*
* timer_period = reload_value x clock_divider / system_clock_frequency
* or
* reload_value = (timer_period * system_clock_frequency) / clock_divider
*
* For timer_period=10mS, and clock_divider=16, that would yield:
*
* reload_value = system_clock_frequency / 1600
*
* For a system timer of 50,000,000 that would result in a reload value of
* 31,250
*
* NOTE: The system clock frequency value is defined in the board.h file
*/
reload = (uint16)(ez80_systemclock / 1600);
outp(EZ80_TMR0_RRH, (ubyte)(reload >> 8));
outp(EZ80_TMR0_RRL, (ubyte)(reload));
/* Clear any pending timer interrupts */
#if defined(_EZ80F91)
reg = inp(EZ80_TMR0_IIR);
#elif defined(_EZ80L92) || defined(_EZ80F92) ||defined(_EZ80F93)
reg = inp(EZ80_TMR0_CTL);
#endif
/* Configure and enable the timer */
#if defined(_EZ80190)
outp(EZ80_TMR0_CTL, 0x5f);
#elif defined(_EZ80F91)
outp(EZ80_TMR0_CTL, (EZ80_TMRCLKDIV_16|EZ80_TMRCTL_TIMCONT|EZ80_TMRCTL_RLD|EZ80_TMRCTL_TIMEN));
#elif defined(_EZ80L92) || defined(_EZ80F92) ||defined(_EZ80F93)
outp(EZ80_TMR0_CTL, 0x57);
#endif
/* Enable timer end-of-count interrupts */
#if defined(_EZ80F91)
outp(EZ80_TMR0_IER, EZ80_TMRIER_EOCEN);
#endif
}
