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/****************************************************************************
* arch/arm/src/lpc313x/lpc313x_timerisr.c
*
* Copyright (C) 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 <stdint.h>
#include <time.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include "clock_internal.h"
#include "up_internal.h"
#include "up_arch.h"
#include "lpc313x_timer.h"
#include "lpc313x_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Function: up_timerisr
*
* Description:
* The timer ISR will perform a variety of services for various portions
* of the systems.
*
****************************************************************************/
int up_timerisr(int irq, uint32_t *regs)
{
/* Clear the lattched timer interrupt (Writing any value to the CLEAR register
* clears the interrupt generated by the counter timer
*/
putreg32(1, LPC313X_TIMER0_CLEAR);
/* Process timer interrupt */
sched_process_timer();
return 0;
}
/****************************************************************************
* Function: up_timerinit
*
* Description:
* This function is called during start-up to initialize
* the timer interrupt.
*
****************************************************************************/
void up_timerinit(void)
{
uint32_t regval;
uint64_t load;
uint64_t freq;
/* Enable the timer0 system clock */
lpc313x_enableclock(CLKID_TIMER0PCLK);
/* Soft reset the timer0 module so that we start in a known state */
lpc313x_softreset(RESETID_TIMER0RST);
/* Set timer load register to 10mS (100Hz). First, get the frequency
* of the timer0 module clock (in the AHB0APB1_BASE domain (2)).
*/
freq = (uint64_t)lpc313x_clkfreq(CLKID_TIMER0PCLK, DOMAINID_AHB0APB1);
/* If the clock is >1MHz, use pre-dividers */
regval = getreg32(LPC313X_TIMER0_CTRL);
if (freq > 1000000)
{
/* Use the divide by 16 pre-divider */
regval &= ~TIMER_CTRL_PRESCALE_MASK;
regval |= TIMER_CTRL_PRESCALE_DIV16;
freq >>= 4;
}
load =((freq * (uint64_t)10000) / 1000000);
putreg32((uint32_t)load, LPC313X_TIMER0_LOAD);
/* Set periodic mode */
regval |= TIMER_CTRL_PERIODIC;
putreg32(regval, LPC313X_TIMER0_CTRL);
/* Attach the timer interrupt vector */
(void)irq_attach(LPC313X_IRQ_TMR0, (xcpt_t)up_timerisr);
/* Clear any latched timer interrupt (Writing any value to the CLEAR register
* clears the latched interrupt generated by the counter timer)
*/
putreg32(1, LPC313X_TIMER0_CLEAR);
/* Enable timers (starts counting) */
regval |= TIMER_CTRL_ENABLE;
putreg32(regval, LPC313X_TIMER0_CTRL);
/* Enable timer match interrupts in the interrupt controller */
up_enable_irq(LPC313X_IRQ_TMR0);
}
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