stm32f4-nucleo-test/libopencm3/tests/gadget-zero/delay_efm32.c
Arti Zirk 2de3a91b0a git subrepo clone https://github.com/libopencm3/libopencm3.git
subrepo:
  subdir:   "libopencm3"
  merged:   "88e91c9a7cce"
upstream:
  origin:   "https://github.com/libopencm3/libopencm3.git"
  branch:   "master"
  commit:   "88e91c9a7cce"
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  origin:   "???"
  commit:   "???"
2023-01-21 18:31:08 +02:00

46 lines
1.3 KiB
C

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