[N32L43X评测] 7.PWM测试
本帖最后由 805721366 于 2022-7-31 09:18 编辑<p><span style="font-family:宋体;">本篇介绍TIM3定时器输出PWM测试</span></p>
<p><span style="color:#f39c12;"><strong><span style="font-family:宋体;">硬件连接</span></strong></span></p>
<p><span style="font-family:宋体;">TIM3CH1 —— PA6</span></p>
<p><span style="font-family:宋体;">TIM3CH2 —— PA7</span></p>
<p class="imagemiddle" style="text-align: center;"></p>
<p><span style="color:#f39c12;"><strong><span style="font-family:宋体;">软件代码</span></strong></span></p>
<p><span style="font-family:宋体;">TIM3输出PWM频率设置为10kHz，CH1占空比50%，CH2占空比25%</span></p>
<pre>
<code>/**
* <a href="home.php?mod=space&uid=159083" target="_blank">@brief</a> PWM初始化
*/
void hal_pwmInitial(void)
{
GPIO_InitType GPIO_InitStructure;
TIM_TimeBaseInitType TIM_TimeBaseStructure;
OCInitType TIM_OCInitStructure;
/* TIM3 clock enable */
RCC_EnableAPB1PeriphClk(RCC_APB1_PERIPH_TIM3, ENABLE);
/* GPIOA and GPIOB clock enable */
RCC_EnableAPB2PeriphClk(RCC_APB2_PERIPH_GPIOA | RCC_APB2_PERIPH_GPIOB | RCC_APB2_PERIPH_AFIO, ENABLE);
GPIO_InitStruct(&GPIO_InitStructure);
/* GPIOA Configuration:TIM3 Channel1, 2, 3 and 4 as alternate function push-pull */
GPIO_InitStructure.Pin = GPIO_PIN_6 | GPIO_PIN_7;
GPIO_InitStructure.GPIO_Mode= GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Current = GPIO_DC_4mA;
GPIO_InitStructure.GPIO_Alternate = GPIO_AF2_TIM3;
GPIO_InitPeripheral(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.Pin = GPIO_PIN_0 | GPIO_PIN_1;
GPIO_InitStructure.GPIO_Alternate = GPIO_AF2_TIM3;
GPIO_InitPeripheral(GPIOB, &GPIO_InitStructure);
/* -----------------------------------------------------------------------
TIM3 Frequency = 54MHz/Prescaler*Period = 54M/54/100 = 10kHz(0.1ms)
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 25%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 75%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 10%
----------------------------------------------------------------------- */
/* Time base configuration */
TIM_TimeBaseStructure.Period = 100-1; //1us*100 = 100us = 0.1ms 10kHz
TIM_TimeBaseStructure.Prescaler = PrescalerValue1; //54000000/54 = 1MHz 1us
TIM_TimeBaseStructure.ClkDiv = 0;
TIM_TimeBaseStructure.CntMode = TIM_CNT_MODE_UP;
TIM_InitTimeBase(TIM3, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.OcMode = TIM_OCMODE_PWM1;
TIM_OCInitStructure.OutputState = TIM_OUTPUT_STATE_ENABLE;
TIM_OCInitStructure.Pulse = CCR1_Value;
TIM_OCInitStructure.OcPolarity= TIM_OC_POLARITY_HIGH;
TIM_InitOc1(TIM3, &TIM_OCInitStructure);
TIM_ConfigOc1Preload(TIM3, TIM_OC_PRE_LOAD_ENABLE);
/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.OutputState = TIM_OUTPUT_STATE_ENABLE;
TIM_OCInitStructure.Pulse = CCR2_Value;
TIM_InitOc2(TIM3, &TIM_OCInitStructure);
TIM_ConfigOc2Preload(TIM3, TIM_OC_PRE_LOAD_ENABLE);
/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.OutputState = TIM_OUTPUT_STATE_ENABLE;
TIM_OCInitStructure.Pulse = CCR3_Value;
TIM_InitOc3(TIM3, &TIM_OCInitStructure);
TIM_ConfigOc3Preload(TIM3, TIM_OC_PRE_LOAD_ENABLE);
/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.OutputState = TIM_OUTPUT_STATE_ENABLE;
TIM_OCInitStructure.Pulse = CCR4_Value;
TIM_InitOc4(TIM3, &TIM_OCInitStructure);
TIM_ConfigOc4Preload(TIM3, TIM_OC_PRE_LOAD_ENABLE);
TIM_ConfigArPreload(TIM3, ENABLE);
/* TIM3 enable counter */
TIM_Enable(TIM3, ENABLE);
}</code></pre>
<p><span style="color:#f39c12;"><span style="font-family:宋体;"><strong>运行测试</strong></span></span></p>
<p></p>
<p></p>
<p><span style="font-family:宋体;"><span style="color:#f39c12;"><strong>测试代码</strong></span></span></p>
<p></p>
<p> </p>
<p>方波效果很好，说明PWM测试代码是正确的吧</p>
两个方波形状非常好，如果频率加高，会不会也一样？ lugl4313820 发表于 2022-8-14 22:06
两个方波形状非常好，如果频率加高，会不会也一样？
<p>测试过，频率加快，输出波形也很好</p>
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