138 lines
4.2 KiB
C
138 lines
4.2 KiB
C
/** esp/timer.h
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*
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* Timer (FRC1 & FRC2) functions.
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*
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* Part of esp-open-rtos
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* Copyright (C) 2015 Superhouse Automation Pty Ltd
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* BSD Licensed as described in the file LICENSE
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*/
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#ifndef _ESP_TIMER_H
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#define _ESP_TIMER_H
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#include <stdbool.h>
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#include <xtensa_interrupts.h>
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#include "esp/registers.h"
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#include "esp/cpu.h"
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typedef enum {
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TIMER_FRC1,
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TIMER_FRC2,
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} timer_frc_t;
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/* Return current count value for timer. */
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INLINED uint32_t timer_get_count(const timer_frc_t frc);
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/* Return current load value for timer. */
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INLINED uint32_t timer_get_load(const timer_frc_t frc);
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/* Write load value for timer. */
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INLINED void timer_set_load(const timer_frc_t frc, const uint32_t load);
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/* Returns maximum load value for timer. */
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INLINED uint32_t timer_max_load(const timer_frc_t frc);
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typedef enum {
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TIMER_DIV1,
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TIMER_DIV16,
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TIMER_DIV256,
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} timer_div_t;
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/* Set the timer divider value */
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INLINED void timer_set_divider(const timer_frc_t frc, const timer_div_t div);
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/* Enable or disable timer interrupts
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This both sets the xtensa interrupt mask and writes to the DPORT register
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that allows timer interrupts.
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*/
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INLINED void timer_set_interrupts(const timer_frc_t frc, bool enable);
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/* Turn the timer on or off */
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INLINED void timer_set_run(const timer_frc_t frc, const bool run);
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/* Get the run state of the timer (on or off) */
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INLINED bool timer_get_run(const timer_frc_t frc);
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/* Set timer auto-reload on or off */
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INLINED void timer_set_reload(const timer_frc_t frc, const bool reload);
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/* Get the auto-reload state of the timer (on or off) */
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INLINED bool timer_get_reload(const timer_frc_t frc);
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/* Return a suitable timer divider for the specified frequency,
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or -1 if none is found.
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*/
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INLINED timer_div_t timer_freq_to_div(uint32_t freq);
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/* Return the number of timer counts to achieve the specified
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* frequency with the specified divisor.
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*
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* frc parameter is used to check out-of-range values for timer size.
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*
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* Returns 0 if the given freq/divisor combo cannot be achieved.
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*
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* Compile-time evaluates if all arguments are available at compile time.
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*/
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INLINED uint32_t timer_freq_to_count(const timer_frc_t frc, uint32_t freq, const timer_div_t div);
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/* Return a suitable timer divider for the specified duration in
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microseconds or -1 if none is found.
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*/
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INLINED timer_div_t timer_time_to_div(uint32_t us);
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/* Return the number of timer counts for the specified timer duration
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* in microseconds, when using the specified divisor.
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*
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* frc paraemter is used to check out-of-range values for timer size.
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*
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* Returns 0 if the given time/divisor combo cannot be achieved.
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*
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* Compile-time evaluates if all arguments are available at compile time.
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*/
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INLINED uint32_t timer_time_to_count(const timer_frc_t frc, uint32_t us, const timer_div_t div);
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/* Set a target timer interrupt frequency in Hz.
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For FRC1 this sets the timer load value and enables autoreload so
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the interrupt will fire regularly with the target frequency.
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For FRC2 this sets the timer match value so the next interrupt
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comes in line with the target frequency. However this won't repeat
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automatically, you have to call timer_set_frequency again when the
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timer interrupt runs.
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Will change the timer divisor value to suit the target frequency.
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Does not start/stop the timer, you have to do this manually via
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timer_set_run.
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Returns true on success, false if given frequency could not be set.
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Compile-time evaluates to simple register writes if all arguments
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are available at compile time.
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*/
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INLINED bool timer_set_frequency(const timer_frc_t frc, uint32_t freq);
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/* Sets the timer for a oneshot interrupt in 'us' microseconds.
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Will change the timer divisor value to suit the target time.
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Does not change the autoreload setting.
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For FRC2 this sets the timer match value relative to the current
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load value.
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Note that for a true "one shot" timeout with FRC1 then you need to
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also disable FRC1 in the timer interrupt handler by calling
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timer_set_run(TIMER_FRC1, false);
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Returns true if the timeout was successfully set.
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Compile-time evaluates to simple register writes if all arguments
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are available at compile time.
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*/
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INLINED bool timer_set_timeout(const timer_frc_t frc, uint32_t us);
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#include "timer_private.h"
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#endif
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