90 lines
1.6 KiB
C
90 lines
1.6 KiB
C
/*
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* Copyright (c) 2006-2018, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2017-09-06 勤为本 first version
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*/
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#include "ls1c_clock.h"
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/*
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* 延时指定时间，单位ms
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* @j 延时时间，单位ms
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*/
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void delay_ms(int j)
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{
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int k_max = clk_get_cpu_rate()/1000/92; // 除以1000表示ms，另外一个除数为实验测得的经验值
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int k = k_max;
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for ( ; j > 0; j--)
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{
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for (k = k_max; k > 0; k--)
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{
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__asm__ ("nop"); // 注意，这里必须用内联汇编，否则会被优化掉
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}
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}
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return ;
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}
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/*
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* 延时指定时间，单位us
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* @n 延时时间，单位us
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*/
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void delay_us(int n)
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{
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int count_1us = 252000000 / 1000000 / 84; // 延时1us的循环次数
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// 252000000为cpu频率，除以1000000表示延时单位为us，92为实验测得的经验值
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int count_max; // 延时n微秒的循环次数
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int tmp;
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// 微调
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count_max = n * count_1us;
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if (10 >= n) // <=10us
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{
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count_max = count_max / 3;
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}
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else if (100 >= n) // <= 100us
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{
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count_max = count_max - count_max / 5;
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}
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else // > 100us
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{
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count_max = count_max - count_max / 10;
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}
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// 延时
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for (tmp = count_max; tmp > 0; tmp--)
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{
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__asm__ ("nop"); // 注意，这里必须用内联汇编，否则会被优化掉
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}
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return ;
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}
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/*
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* 延时指定时间，单位s
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* @i 延时时间，单位s
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*/
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void delay_s(int i)
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{
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for ( ; i > 0; i--)
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{
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delay_ms(1000);
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}
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return ;
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}
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