kopia lustrzana https://github.com/OpenRTX/OpenRTX
52 wiersze
2.4 KiB
C
52 wiersze
2.4 KiB
C
/***************************************************************************
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* Copyright (C) 2020 by Silvano Seva IU2KWO and Niccolò Izzo IU2KIN *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU 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 program 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 General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#include "delays.h"
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/**
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* Implementation of the delay functions for STM32F405 MCU.
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*/
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void delayUs(unsigned int useconds)
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{
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// This delay has been calibrated to take x microseconds
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// It is written in assembler to be independent on compiler optimization
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asm volatile(" mov r1, #42 \n"
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" mul r2, %0, r1 \n"
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" mov r1, #0 \n"
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"___loop_u: cmp r1, r2 \n"
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" itt lo \n"
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" addlo r1, r1, #1 \n"
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" blo ___loop_u \n"::"r"(useconds):"r1","r2");
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}
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void delayMs(unsigned int mseconds)
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{
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register const unsigned int count=42000;
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for(unsigned int i=0;i<mseconds;i++)
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{
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// This delay has been calibrated to take 1 millisecond
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// It is written in assembler to be independent on compiler optimization
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asm volatile(" mov r1, #0 \n"
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"___loop_m: cmp r1, %0 \n"
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" itt lo \n"
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" addlo r1, r1, #1 \n"
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" blo ___loop_m \n"::"r"(count):"r1");
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}
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}
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