/*
ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* @file LPC8xx/gpt_lld.c
* @brief LPC8xx GPT subsystem low level driver source.
*
* @addtogroup GPT
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_GPT || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/**
* @brief GPT1 driver identifier.
* @note The driver GPT1 allocates MRT channel0 when enabled.
*/
#if LPC8xx_GPT_USE_MRT0 || defined(__DOXYGEN__)
GPTDriver GPTD1;
#endif
/**
* @brief GPT2 driver identifier.
* @note The driver GPT1 allocates MRT channel1 when enabled.
*/
#if LPC8xx_GPT_USE_MRT1 || defined(__DOXYGEN__)
GPTDriver GPTD2;
#endif
/**
* @brief GPT3 driver identifier.
* @note The driver GPT1 allocates MRT channel2 when enabled.
*/
#if LPC8xx_GPT_USE_MRT2 || defined(__DOXYGEN__)
GPTDriver GPTD3;
#endif
/**
* @brief GPT4 driver identifier.
* @note The driver GPT1 allocates MRT channel3 when enabled.
*/
#if LPC8xx_GPT_USE_MRT3 || defined(__DOXYGEN__)
GPTDriver GPTD4;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
static uint32_t clk_enabled;
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Shared IRQ handler.
*
* @param[in] gptp pointer to a @p GPTDriver object
* @param[in] irq_flag irq flag bit
*/
static void gpt_lld_serve_interrupt( GPTDriver *gptp ) {
if (gptp->tmr->STAT & 0x01) {
gptp->tmr->STAT |= 0x01;
if (gptp->state == GPT_ONESHOT) {
gptp->state = GPT_READY; /* Back in GPT_READY state. */
}
gptp->config->callback(gptp);
}
return;
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
/**
* @brief MRT IRQ handler.
*
*/
CH_IRQ_HANDLER(Vector68) {
CH_IRQ_PROLOGUE();
#if LPC8xx_GPT_USE_MRT0
gpt_lld_serve_interrupt( &GPTD1 );
#endif
#if LPC8xx_GPT_USE_MRT1
gpt_lld_serve_interrupt( &GPTD2 );
#endif
#if LPC8xx_GPT_USE_MRT2
gpt_lld_serve_interrupt( &GPTD3 );
#endif
#if LPC8xx_GPT_USE_MRT3
gpt_lld_serve_interrupt( &GPTD4 );
#endif
CH_IRQ_EPILOGUE();
}
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level GPT driver initialization.
*
* @notapi
*/
void gpt_lld_init(void) {
#if LPC8xx_GPT_USE_MRT0
GPTD1.tmr = &(LPC_MRT->Channel[0]);
gptObjectInit(&GPTD1);
GPTD1.mask = (1<<0);
#endif
#if LPC8xx_GPT_USE_MRT1
GPTD2.tmr = &(LPC_MRT->Channel[1]);
gptObjectInit(&GPTD2);
GPTD1.mask = (1<<1);
#endif
#if LPC8xx_GPT_USE_MRT2
GPTD3.tmr = &(LPC_MRT->Channel[2]);
gptObjectInit(&GPTD3);
GPTD1.mask = (1<<2);
#endif
#if LPC8xx_GPT_USE_MRT3
GPTD4.tmr = &(LPC_MRT->Channel[3]);
gptObjectInit(&GPTD4);
GPTD1.mask = (1<<3);
#endif
clk_enabled = FALSE;
return;
}
/**
* @brief Configures and activates a GPT channel.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_start(GPTDriver *gptp) {
if( !clk_enabled ) {
/* Enable clock & reset MRT */
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<10);
LPC_SYSCON->PRESETCTRL &= ~(1<<7);
LPC_SYSCON->PRESETCTRL |= (1<<7);
nvicEnableVector(MRT_IRQn,
CORTEX_PRIORITY_MASK(LPC8xx_GPT_MRT_IRQ_PRIORITY));
clk_enabled |= gptp->mask;
}
/* Prescaler value calculation.*/
gptp->pr = (LPC8xx_SYSCLK / gptp->config->frequency);
chDbgAssert((gptp->pr * gptp->config->frequency) == LPC8xx_SYSCLK,
"gpt_lld_start(), #1", "invalid frequency");
/* MRT Channel configuration.*/
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
/**
* @brief Deactivates a GPT channel.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_stop(GPTDriver *gptp) {
/* Shared peripheral -
mark this channel as disabled */
clk_enabled &= ~gptp->mask;
/* All channels disabled? */
if( !clk_enabled )
{
/* Disable periheral */
nvicDisableVector(MRT_IRQn);
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1<<10);
}
return;
}
/**
* @brief Starts the timer in continuous/One shot mode.
*
* @param[in] gptp pointer to the @p GPTDriver object
* @param[in] interval period in ticks
*
* @notapi
*/
void gpt_lld_start_timer(GPTDriver *gptp, gptcnt_t interval) {
gptp->tmr->INTVAL = (1<<31)|((interval*gptp->pr) - 1);
if (gptp->state == GPT_ONESHOT)
gptp->tmr->CTRL = (1<<1)|1;
else
gptp->tmr->CTRL = 1;
}
/**
* @brief Stops the timer.
*
* @param[in] gptp pointer to the @p GPTDriver object
*
* @notapi
*/
void gpt_lld_stop_timer(GPTDriver *gptp) {
gptp->tmr->INTVAL = (1<<31);
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
/**
* @brief Starts the timer in one shot mode and waits for completion.
* @details This function specifically polls the timer waiting for completion
* in order to not have extra delays caused by interrupt servicing,
* this function is only recommended for short delays.
*
* @param[in] gptp pointer to the @p GPTDriver object
* @param[in] interval time interval in ticks
*
* @notapi
*/
void gpt_lld_polled_delay(GPTDriver *gptp, gptcnt_t interval) {
gptp->tmr->INTVAL = (1<<31)|((interval*gptp->pr) - 1);
gptp->tmr->CTRL = (1<<1);
while (gptp->tmr->STAT & (1<<1))
;
gptp->tmr->CTRL = 0;
gptp->tmr->STAT |= 1;
}
#endif /* HAL_USE_GPT */
/** @} */