使用HAL库开发STM32：系统时间基础及进阶使用

文章目录

目的

HAL库默认提供了系统时间，系统时间默认情况下由SysTick定时器计数产生。系统时间一方面用于HAL库自身调用，另一方面用户也可以使用，为开发带来便利。（本文提到的相关使用主要应用于未使用OS（操作系统）的情况下。）

基础使用

一般的系统时间使用方面常用到两个函数：

  • __weak uint32_t HAL_GetTick(void)
    返回从系统运行开始经过的时间，默认情况下单位为ms；
  • __weak void HAL_Delay(uint32_t Delay)
    延时，该延时是阻塞的，默认情况下延时单位为ms，该函数不能在等于或高于系统时钟源优先级（默认情况下为0）的中断程序中使用，不然程序就阻塞在这里不动了；

对于上面两个函数本身来说没什么特别可以多说的，需要注意的点也在上面说明了。上面的延时函数是阻塞型的，当然我们也有方式实现非阻塞的延时。

int main(void)
{
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();

<span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
<span class="token punctuation">{<!-- --></span>
    <span class="token function">HAL_GPIO_TogglePin</span><span class="token punctuation">(</span>GPIOA<span class="token punctuation">,</span> GPIO_PIN_0<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token function">HAL_Delay</span><span class="token punctuation">(</span><span class="token number">1000</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>



}


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上面方式使用HAL_Delay()进行延时，可以实现GPIOA0口每秒反转一次电平。如果只有一个任务这样就没问题，但是如果有多个对延时时间有不同需求的任务这样就不太合适了，这时候可以使用下面方式：

uint32_t previousMillisA0 = 0;
uint32_t previousMillisA1 = 0;

int main(void)

{

HAL_Init();

SystemClock_Config();

MX_GPIO_Init();


<span class="token keyword">while</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
<span class="token punctuation">{<!-- --></span>
    uint32_t currentMillis <span class="token operator">=</span> <span class="token function">HAL_GetTick</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//获取当前系统时间</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>currentMillis <span class="token operator">-</span> previousMillisA0 <span class="token operator">&gt;=</span> <span class="token number">1000</span><span class="token punctuation">)</span> <span class="token comment">//当前时间刻减去前次执行的时间刻</span>
    <span class="token punctuation">{<!-- --></span>
        previousMillisA0 <span class="token operator">=</span> currentMillis<span class="token punctuation">;</span> <span class="token comment">//更新执行时间刻</span>
        <span class="token function">HAL_GPIO_TogglePin</span><span class="token punctuation">(</span>GPIOA<span class="token punctuation">,</span> GPIO_PIN_0<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>currentMillis <span class="token operator">-</span> previousMillisA1 <span class="token operator">&gt;=</span> <span class="token number">500</span><span class="token punctuation">)</span> <span class="token comment">//当前时间刻减去前次执行的时间刻</span>
    <span class="token punctuation">{<!-- --></span>
        previousMillisA1 <span class="token operator">=</span> currentMillis<span class="token punctuation">;</span> <span class="token comment">//更新执行时间刻</span>
        <span class="token function">HAL_GPIO_TogglePin</span><span class="token punctuation">(</span>GPIOA<span class="token punctuation">,</span> GPIO_PIN_1<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>



}


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上面的代码实现了GPIOA0口每秒反转一次电平，同时GPIOA1口每500毫秒反转一次电平。可以使用这种方式处理更多的任务。

进阶使用

HAL的系统时间由定时器在中断中累加计数：

/**
  * @brief This function is called to increment  a global variable "uwTick"
  *        used as application time base.
  * @note In the default implementation, this variable is incremented each 1ms
  *       in SysTick ISR.
 * @note This function is declared as __weak to be overwritten in case of other 
  *      implementations in user file.
  * @retval None
  */
__weak void HAL_IncTick(void)
{
  uwTick += uwTickFreq;
}

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因为这个回调函数是由 __weak 符号修饰的，所以可以自己重新写同名函数来实现更复杂的功能，比如可以用来实现调度器功能。先看下面演示：
在这里插入图片描述
上图例子中声明了两个任务，分别设置运行参数并运行。通过图中可以看到两个任务都按期望的方式执行了。

以下是Ticker部分代码：

#ifndef LIB_TICKER_H_
#define LIB_TICKER_H_

#include "main.h"


#define LIB_TICKER_MAX_SIZE 16 // 最大Ticker可绑定数


class LibTicker {

public:

LibTicker(void);

~LibTicker(void);


<span class="token keyword">typedef</span> <span class="token keyword">void</span> <span class="token punctuation">(</span><span class="token operator">*</span>callback_t<span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">typedef</span> <span class="token keyword">void</span> <span class="token punctuation">(</span><span class="token operator">*</span>callback_with_arg_t<span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token operator">*</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 设置Ticker定期执行，输入参数分别是时间（毫秒）、回调函数</span>
bool <span class="token function">attach</span><span class="token punctuation">(</span>size_t milliseconds<span class="token punctuation">,</span> callback_t callback<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
	<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>milliseconds<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
		<span class="token keyword">return</span> false<span class="token punctuation">;</span>
	<span class="token punctuation">}</span>
	<span class="token keyword">return</span> <span class="token function">_attach</span><span class="token punctuation">(</span>milliseconds<span class="token punctuation">,</span> milliseconds<span class="token punctuation">,</span> reinterpret_cast<span class="token operator">&lt;</span>callback_with_arg_t<span class="token operator">&gt;</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 设置Ticker定期执行，输入参数分别是时间（毫秒）、回调函数、不大于32位变量</span>
template<span class="token operator">&lt;</span>typename T<span class="token operator">&gt;</span>
bool <span class="token function">attach</span><span class="token punctuation">(</span>size_t milliseconds<span class="token punctuation">,</span> <span class="token keyword">void</span> <span class="token punctuation">(</span><span class="token operator">*</span>callback<span class="token punctuation">)</span><span class="token punctuation">(</span>T<span class="token punctuation">)</span><span class="token punctuation">,</span> T arg<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
	<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>milliseconds<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
		<span class="token keyword">return</span> false<span class="token punctuation">;</span>
	<span class="token punctuation">}</span>
	<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">sizeof</span><span class="token punctuation">(</span>T<span class="token punctuation">)</span> <span class="token operator">&gt;</span> <span class="token keyword">sizeof</span><span class="token punctuation">(</span>size_t<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
		<span class="token keyword">return</span> false<span class="token punctuation">;</span>
	<span class="token punctuation">}</span>
	uint32_t arg32 <span class="token operator">=</span> <span class="token punctuation">(</span>uint32_t<span class="token punctuation">)</span> arg<span class="token punctuation">;</span>
	<span class="token keyword">return</span> <span class="token function">_attach</span><span class="token punctuation">(</span>milliseconds<span class="token punctuation">,</span> milliseconds<span class="token punctuation">,</span> reinterpret_cast<span class="token operator">&lt;</span>callback_with_arg_t<span class="token operator">&gt;</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">,</span> arg32<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 设置Ticker执行一次，输入参数分别是时间（毫秒）、回调函数</span>
bool <span class="token function">once</span><span class="token punctuation">(</span>size_t milliseconds<span class="token punctuation">,</span> callback_t callback<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
	<span class="token keyword">return</span> <span class="token function">_attach</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> milliseconds<span class="token punctuation">,</span> reinterpret_cast<span class="token operator">&lt;</span>callback_with_arg_t<span class="token operator">&gt;</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token comment">// 设置Ticker执行一次，输入参数分别是时间（毫秒）、回调函数、不大于32位变量</span>
template<span class="token operator">&lt;</span>typename T<span class="token operator">&gt;</span>
bool <span class="token function">once</span><span class="token punctuation">(</span>size_t milliseconds<span class="token punctuation">,</span> <span class="token keyword">void</span> <span class="token punctuation">(</span><span class="token operator">*</span>callback<span class="token punctuation">)</span><span class="token punctuation">(</span>T<span class="token punctuation">)</span><span class="token punctuation">,</span> T arg<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
	<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">sizeof</span><span class="token punctuation">(</span>T<span class="token punctuation">)</span> <span class="token operator">&gt;</span> <span class="token keyword">sizeof</span><span class="token punctuation">(</span>size_t<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
		<span class="token keyword">return</span> false<span class="token punctuation">;</span>
	<span class="token punctuation">}</span>
	uint32_t arg32 <span class="token operator">=</span> <span class="token punctuation">(</span>uint32_t<span class="token punctuation">)</span> arg<span class="token punctuation">;</span>
	<span class="token keyword">return</span> <span class="token function">_attach</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> milliseconds<span class="token punctuation">,</span> reinterpret_cast<span class="token operator">&lt;</span>callback_with_arg_t<span class="token operator">&gt;</span><span class="token punctuation">(</span>callback<span class="token punctuation">)</span><span class="token punctuation">,</span> arg32<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">void</span> <span class="token function">detach</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 停止已绑定运行的Ticker</span>
bool <span class="token function">active</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 返回Ticker当前是否已绑定</span>
<span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">handle</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 执行已就绪的任务，该函数可以设置成main(){while(1){LibTicker::handle();}}</span>
<span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">schedule</span><span class="token punctuation">(</span><span class="token keyword">void</span><span class="token punctuation">)</span><span class="token punctuation">;</span>



private:

bool _active;

size_t _index;

bool _ready;

size_t _period;

size_t _count;

callback_with_arg_t _callback;

size_t _arg;

bool _attach(size_t period, size_t count, callback_with_arg_t callback, size_t arg);

static LibTicker *_ticker[LIB_TICKER_MAX_SIZE];

};


#endif /* LIB_TICKER_H_ */


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#include "lib_ticker.h"

typedef void (*LibTickerCallBack)(size_t arg);


LibTicker::LibTicker(void) :

_active(false), _ready(false), _period(0), _count(0), _callback(nullptr), _arg(0) {

}


LibTicker::~LibTicker(void) {

detach();

}


void LibTicker::detach(void) {

if (_active) { // 如果Ticker当前已绑定运行

__disable_irq();

_active = false;

_ready = false;

_period = 0;

_callback = nullptr;

_arg = 0;

_ticker[_index] = nullptr;

__enable_irq();

}

}


bool LibTicker::active(void) {

return _active;

}


bool LibTicker::_attach(size_t period, size_t count, callback_with_arg_t callback, size_t arg) {

if (callback  nullptr) {

return false;

}

if (_active) { // 如果Ticker当前已绑定运行

_ready = false;

_period = period;

_count = count;

_callback = callback;

_arg = arg;

return true;

} else {

for (size_t i = 0; i < LIB_TICKER_MAX_SIZE; i++) {

if (_ticker[i]  nullptr) {

__disable_irq();

_active = true;

_index = i;

_ready = false;

_period = period;

_count = count;

_callback = callback;

_arg = arg;

_ticker[i] = this;

if (_count == 0) {

_ready = true;

}

__enable_irq();

return true;

}

}

}

return false;

}


void LibTicker::handle(void) {

for (size_t i = 0; i < LIB_TICKER_MAX_SIZE; i++) {

if (_ticker[i]  nullptr) {

continue;

}

if (!_ticker[i]->_active) {

continue;

}

if (_ticker[i]->_ready) { // 当前Ticker已就绪

_ticker[i]->_ready = false;

_ticker[i]->_callback(reinterpret_cast<void*>(_ticker[i]->_arg));

if ((_ticker[i]->_period  0) && (_ticker[i]->_count == 0)) { // 该任务只运行一次

_ticker[i]->detach();

}

}

}

}


void LibTicker::schedule(void) {

for (size_t i = 0; i < LIB_TICKER_MAX_SIZE; i++) {

if (_ticker[i]  nullptr) {

continue;

}

if (!_ticker[i]->_active) {

continue;

}

if (_ticker[i]->_count) {

_ticker[i]->_count--;

}

if (_ticker[i]->_count  0) {

_ticker[i]->_ready = true;

_ticker[i]->_count = _ticker[i]->_period;

}

}

}


LibTicker * LibTicker::_ticker[LIB_TICKER_MAX_SIZE] = { nullptr };


extern __IO uint32_t uwTick;

extern HAL_TickFreqTypeDef uwTickFreq;

void HAL_IncTick(void) { // 重写系统时间计数函数

uwTick += uwTickFreq; // 保留系统时间计数功能

LibTicker::schedule(); // 进行Ticker调度处理

}


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上面的例子打包下载：
《基于STM32 HAL库的定时任务调度器例程 stm32f405ticker.zip》
https://download.csdn.net/download/naisu_kun/11913140
另外也可以参考GitHub上项目，命名稍有调整，功能并没有改动：
https://github.com/NaisuXu/STM32-tool-library-based-on-HAL-and-LL

总结

系统时间在开发过程中还是比较有用的，上面只是列举了部分常见用法。如果对时间有更精密的需求的话推荐使用定时器。

posted @ 2023-07-21 08:35  SymPny  阅读(451)  评论(0)  编辑  收藏  举报