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*/ | |
/** \addtogroup pit_module Working with PIT | |
* \section Purpose | |
* The PIT driver provides the Interface for configuration the Periodic | |
* Interval Timer (PIT) peripheral. | |
* | |
* \section Usage | |
* <ul> | |
* <li> Initialize the PIT with the desired period using pit_init(). | |
* Alternatively, the Periodic Interval Value (PIV) can be configured | |
* manually using pit_set_piv(). </li> | |
* <li> Start the PIT counting using pit_enable(). | |
* <li> Enable & disable the PIT interrupt using pit_enable_it() and | |
* pit_disable_it(). </li> | |
* <li> Retrieve the current status of the PIT using pit_get_status(). </li> | |
* <li> To get the current value of the internal counter and the number of ticks | |
* that have occurred, use either pit_get_pivr() or pit_get_piir() depending | |
* on whether you want the values to be cleared or not. </li> | |
* | |
* </ul> | |
* For more accurate information, please look at the PIT section of the | |
* Datasheet. | |
* | |
* Related files :\n | |
* \ref pit.c\n | |
* \ref pit.h.\n | |
*/ | |
/*@{*/ | |
/*@}*/ | |
/** | |
* \file | |
* | |
* Implementation of PIT (Periodic Interval Timer) controller. | |
* | |
*/ | |
/*------------------------------------------------------------------------------ | |
* Headers | |
*------------------------------------------------------------------------------*/ | |
#include "chip.h" | |
#include "peripherals/pit.h" | |
#include "peripherals/pmc.h" | |
/*------------------------------------------------------------------------------ | |
* Exported functions | |
*------------------------------------------------------------------------------*/ | |
void pit_init(uint32_t period) | |
{ | |
uint32_t pit_frequency = pmc_get_peripheral_clock(ID_PIT) / 1000000; | |
PIT->PIT_MR = period ? (period * pit_frequency + 8) >> 4 : 0; | |
PIT->PIT_MR |= PIT_MR_PITEN; | |
} | |
void pit_set_piv(uint32_t piv) | |
{ | |
uint32_t dwMr = PIT->PIT_MR & (~PIT_MR_PIV_Msk); | |
PIT->PIT_MR = dwMr | PIT_MR_PIV(piv); | |
} | |
void pit_enable(void) | |
{ | |
PIT->PIT_MR |= PIT_MR_PITEN; | |
} | |
void pit_disable(void) | |
{ | |
PIT->PIT_MR &= ~PIT_MR_PITEN; | |
} | |
void pit_enable_it(void) | |
{ | |
PIT->PIT_MR |= PIT_MR_PITIEN; | |
} | |
void pit_disable_it(void) | |
{ | |
PIT->PIT_MR &= ~PIT_MR_PITIEN; | |
} | |
uint32_t pit_get_mode(void) | |
{ | |
return PIT->PIT_MR; | |
} | |
uint32_t pit_get_status(void) | |
{ | |
return PIT->PIT_SR; | |
} | |
uint32_t pit_get_piir(void) | |
{ | |
return PIT->PIT_PIIR; | |
} | |
uint32_t pit_get_pivr(void) | |
{ | |
return PIT->PIT_PIVR; | |
} |