/*
* LPC22XX/LPC21xx clock specific using the System Timer
* Copyright (c) 2006 by Ray <rayx.cn@gmail.com>
* Set the Time0 to generate click for RTEMS
*
* This is hardware specific part of the clock driver. At the end of this
* file, the generic part of the driver is #included.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <rtems.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <lpc22xx.h>
#include <rtems/bspIo.h> /* for printk */
void Clock_isr(rtems_irq_hdl_param arg);
static void clock_isr_on(const rtems_irq_connect_data *unused);
static void clock_isr_off(const rtems_irq_connect_data *unused);
static int clock_isr_is_on(const rtems_irq_connect_data *irq);
/* Replace the first value with the clock's interrupt name. */
rtems_irq_connect_data clock_isr_data = {
.name = LPC22xx_INTERRUPT_TIMER0,
.hdl = Clock_isr,
.handle = NULL,
.on = clock_isr_on,
.off = clock_isr_off,
.isOn = clock_isr_is_on,
};
/* use the /shared/clockdrv_shell.h code template */
/**
* When we get the clock interrupt
* - clear the interrupt bit?
* - restart the timer?
*/
#define Clock_driver_support_at_tick() \
do { \
if (!(T0IR & 0x01)) \
return; \
T0IR = 0x01; \
VICVectAddr = 0x00; \
} while(0)
/**
* Installs the clock ISR. You shouldn't need to change this.
*/
#define Clock_driver_support_install_isr( _new, _old ) \
do { \
(_old) = NULL; \
BSP_install_rtems_irq_handler(&clock_isr_data); \
} while(0)
/**
* Initialize the hardware for the clock
* - Set the frequency
* - enable it
* - clear any pending interrupts
*
* Since you may want the clock always running, you can
* enable interrupts here. If you do so, the clock_isr_on(),
* clock_isr_off(), and clock_isr_is_on() functions can be
* NOPs.
*
* set timer to generate interrupt every
* rtems_configuration_get_microseconds_per_tick()
* MR0/(LPC22xx_Fpclk/(PR0+1)) = 10/1000 = 0.01s
*/
#define Clock_driver_support_initialize_hardware() \
do { \
/* disable and clear timer 0, set to */ \
T0TCR &= 0; \
/* TC is incrementet on every pclk.*/ \
T0PC = 0; \
/* initialize the timer period and prescaler */ \
T0MR0 = ((LPC22xx_Fpclk/1000 * \
rtems_configuration_get_microseconds_per_tick()) / 1000); \
/* generate interrupt when T0MR0 match T0TC and Reset Timer Count*/ \
T0MCR |= 0x03; \
/* No external match */ \
T0EMR = 0; \
/* enable timer0 */ \
T0TCR = 1; \
/* enable interrupt, skyeye will check this*/ \
T0IR |= 0x01; \
} while (0)
/**
* Do whatever you need to shut the clock down and remove the
* interrupt handler. Since this normally only gets called on
* RTEMS shutdown, you may not need to do anything other than
* remove the ISR.
*/
#define Clock_driver_support_shutdown_hardware() \
do { \
/* Disable timer */ \
T0TCR&=~0x02; \
BSP_remove_rtems_irq_handler(&clock_isr_data); \
} while (0)
uint32_t bsp_clock_nanoseconds_since_last_tick(void)
{
uint32_t clicks;
uint32_t microseconds;
clicks = T0TC; /* T0TC is the 32bit time counter 0 */
microseconds = (rtems_configuration_get_microseconds_per_tick() - clicks);
return microseconds * 1000;
}
#define Clock_driver_nanoseconds_since_last_tick \
bsp_clock_nanoseconds_since_last_tick
/**
* Enables clock interrupt.
*
* If the interrupt is always on, this can be a NOP.
*/
static void clock_isr_on(const rtems_irq_connect_data *unused)
{
T0IR&=0x01;
}
/**
* Disables clock interrupts
*
* If the interrupt is always on, this can be a NOP.
*/
static void clock_isr_off(const rtems_irq_connect_data *unused)
{
T0IR=0x00;
}
/**
* Tests to see if clock interrupt is enabled, and returns 1 if so.
* If interrupt is not enabled, returns 0.
*
* If the interrupt is always on, this always returns 1.
*/
static int clock_isr_is_on(const rtems_irq_connect_data *irq)
{
return T0IR & 0x01; /* MR0 mask */
}
/* Make sure to include this, and only at the end of the file */
#include "../../../../libbsp/shared/clockdrv_shell.h"
