52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
/**
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* @file timer.c
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* @brief Hardware timer for DAP timestamp
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* @change: 2021-02-18 Using the FRC2 timer
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*
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* @version 0.2
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* @date 2020-01-22
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*
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* @copyright Copyright (c) 2021
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*
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*/
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#include <stdint.h>
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#include <stdbool.h>
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#include "timer.h"
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#include "hw_timer.h"
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#include "timer_struct.h"
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#include "cmsis_compiler.h"
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/event_groups.h"
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/*
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Note:
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System bus frequency is 80MHz, will not be affected by CPU frequency. The
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frequency of UART, SPI, or other peripheral devices, are divided from system
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bus frequency, so they will not be affected by CPU frequency either.
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*/
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#define TIMER_BASE 0x60000600
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volatile frc2_struct_t * frc2 = (frc2_struct_t *)(TIMER_BASE + (1) * 0x20);
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void timer_init()
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{
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vPortEnterCritical();
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frc2->ctrl.div = TIMER_CLKDIV_16; // 80MHz / 16 = 5MHz
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frc2->ctrl.intr_type = TIMER_EDGE_INT;
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frc2->ctrl.reload = 0x01; // enable auto reload
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frc2->load.val = 0x7FFFFFFF; // 31bit max
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frc2->ctrl.en = 0x01;
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vPortExitCritical();
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}
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// Timing up to 2147483647(0x7FFFFFFF) / 5000000(5MHz) = 429s
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// 0.2 micro-second resolution
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uint32_t get_timer_count()
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{
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return (uint32_t)frc2->count.data;
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} |