97 lines
2.9 KiB
C
97 lines
2.9 KiB
C
/**
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* \file
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*
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* \brief ARM functions for busy-wait delay loops
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*
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* Copyright (c) 2014-2015 Atmel Corporation. All rights reserved.
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*
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* \asf_license_start
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*
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* \page License
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. The name of Atmel may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* 4. This software may only be redistributed and used in connection with an
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* Atmel microcontroller product.
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*
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* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* \asf_license_stop
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*
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*/
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/*
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* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
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*/
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#include "delay.h"
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/**
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* Value used to calculate ms delay. Default to be used with a 8MHz clock;
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*/
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static uint32_t cycles_per_ms = 8000000UL / 1000;
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static uint32_t cycles_per_us = 8000000UL / 1000000;
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/**
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* \brief Initialize the delay driver.
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*
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* This must be called during start up to initialize the delay routine with
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* the current used main clock. It must run any time the main CPU clock is changed.
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*/
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void delay_init(void)
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{
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cycles_per_ms = system_gclk_gen_get_hz(0);
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cycles_per_ms /= 1000;
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cycles_per_us = cycles_per_ms / 1000;
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SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk;
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}
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/**
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* \brief Delay loop to delay at least n number of microseconds
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*
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* \param n Number of microseconds to wait
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*/
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void delay_cycles_us(
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uint32_t n)
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{
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while (n--) {
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/* Divide up to blocks of 10u */
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delay_cycles(cycles_per_us);
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}
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}
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/**
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* \brief Delay loop to delay at least n number of milliseconds
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*
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* \param n Number of milliseconds to wait
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*/
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void delay_cycles_ms(
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uint32_t n)
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{
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while (n--) {
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/* Divide up to blocks of 1ms */
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delay_cycles(cycles_per_ms);
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}
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}
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