46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
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/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2018 Seb Holzapfel <schnommus@gmail.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <libopencm3/efm32/cmu.h>
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#include <libopencm3/efm32/timer.h>
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#include "delay.h"
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extern const uint32_t ahb_frequency;
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void delay_setup(void)
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{
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cmu_periph_clock_enable(CMU_TIMER2);
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/* efm32hg doesn't support a nice 1us prescaler */
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timer_start(TIMER2);
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}
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void delay_us(uint16_t us)
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{
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volatile uint16_t time_now = 0;
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/* Convert microseconds into timer ticks */
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uint16_t delay_ahb_cycles = us * (ahb_frequency / 1000000);
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TIMER2_CNT = 0;
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while (time_now < delay_ahb_cycles) {
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time_now = TIMER2_CNT;
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}
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}
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