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136 lines
3.7 KiB
C
136 lines
3.7 KiB
C
/*
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* Copyright (C) 2013 Freie Universität Berlin
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*
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* This file subject to the terms and conditions of the GNU Lesser General
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* Public License. See the file LICENSE in the top level directory for more
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* details.
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*/
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/**
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* @defgroup core_hwtimer Hardware timer
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* @ingroup core
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* @brief Hardware timer interface
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*
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* The Hardware timers are directly mapped to hardware timers with minimum
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* latency. They are intended for short intervals and to be used in time
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* critical low-level drivers (e.g. radio). hwtimer callbacks are run in the
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* interrupt context and must use the shortest possible execution time (e.g.
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* set a flag and trigger a worker thread).
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*
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* <b>The hardware timer must not be used within applications</b>, use \ref vtimer
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* instead.
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*
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* @{
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*
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* @file hwtimer.h
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* @brief HW-timer abstraction
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*
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* @author Freie Universität Berlin, Computer Systems & Telematics
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* @author Heiko Will
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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* @author Michael Baar
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*/
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#ifndef __HWTIMER_H
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#define __HWTIMER_H
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#include <stdint.h>
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#include "hwtimer_cpu.h"
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/**
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* @def HWTIMER_SPEED
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* @brief Number of kernel timer ticks per second
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*/
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#ifndef HWTIMER_SPEED
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#warning "HWTIMER_SPEED undefined. Set HWTIMER_SPEED to number of ticks per second for the current architecture."
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#endif
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/**
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* @brief Convert microseconds to kernel timer ticks
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* @param[in] us number of microseconds
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* @return kernel timer ticks
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*/
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#define HWTIMER_TICKS(us) ((us) / (1000000L / HWTIMER_SPEED))
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/**
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* @brief Convert ticks to microseconds
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* @param[in] ticks number of ticks
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* @return microseconds
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*/
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#define HWTIMER_TICKS_TO_US(ticks) ((ticks) * (1000000L/HWTIMER_SPEED))
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/**
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* @def HWTIMER_MAXTICKS
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* @brief Maximum hwtimer tick count (before overflow)
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*/
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#ifndef HWTIMER_MAXTICKS
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#warning "HWTIMER_MAXTICKS undefined. Set HWTIMER_MAXTICKS to maximum number of ticks countable on the current architecture."
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#endif
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/**
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* @brief microseconds before hwtimer overflow
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*/
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#define HWTIMER_OVERFLOW_MICROS() (1000000L / HWTIMER_SPEED * HWTIMER_MAXTICKS)
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typedef uint32_t timer_tick_t;
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void hwtimer_init(void);
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void hwtimer_init_comp(uint32_t fcpu);
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/**
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* @brief Get the hardware time
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* @return The current tick count of the hardware timer
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*/
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unsigned long hwtimer_now(void);
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/**
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* @brief Set a kernel timer
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* @param[in] offset Offset until callback invocation in timer ticks
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* @param[in] callback Callback function
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* @param[in] ptr Argument to callback function
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* @return timer id
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*/
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int hwtimer_set(unsigned long offset, void (*callback)(void*), void *ptr);
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/**
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* @brief Set a kernel timer
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* @param[in] absolute Absolute timer counter value for invocation of handler
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* @param[in] callback Callback function
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* @param[in] ptr Argument to callback function
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* @return timer id
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*/
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int hwtimer_set_absolute(unsigned long absolute, void (*callback)(void*), void *ptr);
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/**
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* @brief Remove a kernel timer
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* @param[in] t Id of timer to remove
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* @retval 1 on success
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*/
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int hwtimer_remove(int t);
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/**
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* @brief Delay current thread
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* @param[in] ticks Number of kernel ticks to delay
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*/
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void hwtimer_wait(unsigned long ticks);
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/**
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* @brief Delay current thread, spinning. Use only in interrupts for VERY short delays!
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* @param[in] ticks Number of kernel ticks to delay
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*/
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void hwtimer_spin(unsigned long ticks);
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int hwtimer_active(void);
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/** @} */
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/* internal */
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/**
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* @brief TODO
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* @internal
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*/
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void hwtimer_cpu_init(void (*handler)(int), uint32_t fcpu);
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/** @} */
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#endif /* __HWTIMER_H */
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