本文主要是介绍STM32 TIM 多通道互补PWM波形输出配置快速入门,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
platform
:stm32f10xxx
lib
:STM32F10x_StdPeriph_Lib_V3.5.0
前言
在做三相逆变的时候,需要软件生成SVPWM
波形,具体的算法需要产生三对互补的PWM
,这样可以驱动六个开关元件,stm32f103
中的TIM1
高级定时器支持产生三路互补PWM
波形,下面进一步学习。
PWM产生的原理
TIM1
的OC
模块,可以产生PWM
波形,具体步骤;
- 寄存器
TIMx CNT
每过一个时钟周期就会加1
; - 然后
TIMx CNT
的值与TIMx CCER
进行比较; - 最终改变
OC
上的有效电平;
以上只需要配置好TIM1
的寄存器即可,无需再编程干预,当然可以动态修改TIMx CCER
的值,从而改变占空比。可以参考下图;
PWM模式
这里主要对PWM模式进行配置的时候做一下区分,存在以下两种情况;
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
那么TIM_OCMode_PWM1
和TIM_OCMode_PWM2
有什么区别呢?
- TIM_OCMode_PWM1 PWM模式1
在向上计数时,一旦TIMx_CNT<TIMx_CCR1时通道1为有效电平,否则为无效电平
在向下计数时,一旦TIMx_CNT>TIMx_CCR1时通道1为无效电平(OC1REF=0),否则为有效 电平(OC1REF=1)。 - TIM_OCMode_PWM2 PWM模式2
在向上计数时,一旦TIMx_CNT<TIMx_CCR1时通道1为无效电平,否则为有效电平
在向下计数时,一旦TIMx_CNT>TIMx_CCR1时通道1为有效电平,否则为无效电平。
死区插入和刹车功能
互补PWM
还支持插入死区时间,最主要的寄存器是TIMx_BDTR
,在标准库中把相关的变量封装到TIM_BDTRInitTypeDef
结构体中;具体如下;
typedef struct
{uint16_t TIM_OSSRState; /*!< Specifies the Off-State selection used in Run mode.This parameter can be a value of @ref OSSR_Off_State_Selection_for_Run_mode_state */uint16_t TIM_OSSIState; /*!< Specifies the Off-State used in Idle state.This parameter can be a value of @ref OSSI_Off_State_Selection_for_Idle_mode_state */uint16_t TIM_LOCKLevel; /*!< Specifies the LOCK level parameters.This parameter can be a value of @ref Lock_level */ uint16_t TIM_DeadTime; /*!< Specifies the delay time between the switching-off and theswitching-on of the outputs.This parameter can be a number between 0x00 and 0xFF */uint16_t TIM_Break; /*!< Specifies whether the TIM Break input is enabled or not. This parameter can be a value of @ref Break_Input_enable_disable */uint16_t TIM_BreakPolarity; /*!< Specifies the TIM Break Input pin polarity.This parameter can be a value of @ref Break_Polarity */uint16_t TIM_AutomaticOutput; /*!< Specifies whether the TIM Automatic Output feature is enabled or not. This parameter can be a value of @ref TIM_AOE_Bit_Set_Reset */
} TIM_BDTRInitTypeDef;
相关的含义看注释可以知道大概意思;这里整理了几个比较重要的变量;
- 死区时间
TIM_DeadTime
的计算;TIMx_BDTR
的低八位的配置决定了死区的时间;
UTG[7:0]
: 死区发生器设置 (Dead-time generator setup
)
这些位定义了插入互补输出之间的死区持续时间。假设DT表示其持续时间:
DTG[7:5]=0xx => DT=DTG[7:0] × Tdtg | Tdtg = TDTS; |
DTG[7:5]=10x => DT=(64+DTG[5:0]) × Tdtg | Tdtg = 2 × TDTS; |
DTG[7:5]=110 => DT=(32+DTG[4:0]) × Tdtg | Tdtg = 8 × TDTS; |
DTG[7:5]=111 => DT=(32+DTG[4:0])× Tdtg | Tdtg = 16 × TDTS; |
例:若TDTS = 125ns(8MHZ),可能的死区时间为:
0到15875ns,若步长时间为125ns;
16us到31750ns,若步长时间为250ns;
32us到63us,若步长时间为1us;
64us到126us,若步长时间为2us;
注:一旦LOCK级别(TIMx_BDTR寄存器中的LOCK位)设为1、 2或3,则不能修改这些位。
TIM_Break
则表示是否决定使用刹车,如果发生错误,则可以通过刹车,第一时间停止PWM
波形的产生,从而保证了系统的安全性;
代码实现
#include "stm32f10x.h"
#include "svpwm_driver.h"
#include "stm32f10x_tim.h"
#include "stm32f10x_it.h"
#include <stdio.h>#define SVPWM_USE_BDT 1
#define USE_HARD_PWM 1
/*** @brief Configures the different system clocks.* @param None* @retval None*/
void pwm_rcc_init(void)
{/* TIM1, GPIOA, GPIOB, GPIOE and AFIO clocks enable */RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO |RCC_APB2Periph_GPIOB, ENABLE);
}void pwm_cnt_irq_init(void)
{}/*** @brief Configure the TIM1 Pins.* @param None* @retval None* @note* PA8 /T1_CH1 ---> HIn3* PA9 /T1_CH2 ---> HIn2* PA10/T1_CH3 ---> HIn1* Out2 ---> PA0/ADC0* Out3 ---> PA1/ADC1* PB15/T1_CHN3 ---> LIn1* PB14/T1_CHN2 ---> LIn2* PB13/T1_CHN1 ---> LIn3*/
void pwm_pin_init(void)
{GPIO_InitTypeDef GPIO_InitStructure;/* GPIOA Configuration: Channel 1, 2 and 3 as alternate function push-pull */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 ;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA, &GPIO_InitStructure);/* GPIOB Configuration: Channel 1N, 2N and 3N as alternate function push-pull */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;GPIO_Init(GPIOB, &GPIO_InitStructure);
}void pwm_tim_init(void){TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;TIM_OCInitTypeDef TIM_OCInitStructure;TIM_BDTRInitTypeDef TIM_BDTRInitStructure;
// NVIC_InitTypeDef NVIC_InitStructure;uint16_t TimerPeriod = 0;uint16_t Channel1Pulse = 0, Channel2Pulse = 0, Channel3Pulse = 0;/* TIM1 Configuration ---------------------------------------------------Generate 7 PWM signals with 4 different duty cycles:TIM1CLK = SystemCoreClock, Prescaler = 0, TIM1 counter clock = SystemCoreClockSystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-densityand Connectivity line devices and to 24 MHz for Low-Density Value line andMedium-Density Value line devicesThe objective is to generate 7 PWM signal at 17.57 KHz:- TIM1_Period = (SystemCoreClock / 17570) - 1The channel 1 and channel 1N duty cycle is set to 50%The channel 2 and channel 2N duty cycle is set to 50%The channel 3 and channel 3N duty cycle is set to 50%The Timer pulse is calculated as follows:- ChannelxPulse = DutyCycle * (TIM1_Period - 1) / 100----------------------------------------------------------------------- */TimerPeriod = (SYS_FRQ / PWM_FRQ ) - 1;/* Compute CCR1 value to generate a duty cycle at 50% for channel 1 and 1N */Channel1Pulse = (uint16_t) (((uint32_t) PWM_DUTY * (TimerPeriod - 1)) / 100);/* Compute CCR2 value to generate a duty cycle at 37.5% for channel 2 and 2N */Channel2Pulse = (uint16_t) (((uint32_t) PWM_DUTY * (TimerPeriod - 1)) / 100);/* Compute CCR3 value to generate a duty cycle at 25% for channel 3 and 3N */Channel3Pulse = (uint16_t) (((uint32_t) PWM_DUTY * (TimerPeriod - 1)) / 100);//TIM_DeInit(TIM1);/* Time Base configuration */TIM_TimeBaseStructure.TIM_Prescaler = TIM_PSCReloadMode_Update;//TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned2;TIM_TimeBaseStructure.TIM_Period = TimerPeriod;TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);/*TIM_ClearFlag(TIM1, TIM_FLAG_Update);TIM_ITConfig(TIM1,TIM_IT_Update, ENABLE);NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_InitStructure); *//* Channel 1, 2, 3 Configuration in PWM mode */#if USE_HARD_PWM/** TIM_OCMode_PWM1 PWM模式1在向上计数时,一旦TIMx_CNT<TIMx_CCR1时通道1为有效电平,否则为无效电平在向下计数时,一旦TIMx_CNT>TIMx_CCR1时通道1为无效电平(OC1REF=0),否则为有效 电平(OC1REF=1)。TIM_OCMode_PWM2 PWM模式2在向上计数时,一旦TIMx_CNT<TIMx_CCR1时通道1为无效电平,否则为有效电平在向下计数时,一旦TIMx_CNT>TIMx_CCR1时通道1为有效电平,否则为无效电平。*/ TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;TIM_OCInitStructure.TIM_Pulse = Channel1Pulse;TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCPolarity_High;TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;TIM_OC1Init(TIM1, &TIM_OCInitStructure);TIM_OCInitStructure.TIM_Pulse = Channel2Pulse;TIM_OC2Init(TIM1, &TIM_OCInitStructure);TIM_OCInitStructure.TIM_Pulse = Channel3Pulse;TIM_OC3Init(TIM1, &TIM_OCInitStructure);TIM_OC1PreloadConfig(TIM1,TIM_OCPreload_Enable);TIM_OC2PreloadConfig(TIM1,TIM_OCPreload_Enable);TIM_OC3PreloadConfig(TIM1,TIM_OCPreload_Enable);#endif #if SVPWM_USE_BDTTIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable;TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable;TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_OFF;TIM_BDTRInitStructure.TIM_DeadTime = 30;TIM_BDTRInitStructure.TIM_Break = TIM_Break_Disable; TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_Low;TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Disable;TIM_BDTRConfig(TIM1, &TIM_BDTRInitStructure);
#endif TIM_CCPreloadControl(TIM1,ENABLE);/* TIM1 counter enable */ TIM_Cmd(TIM1, ENABLE);/* TIM1 Main Output Enable */TIM_CtrlPWMOutputs(TIM1, ENABLE);
}void pwm_init(void){pwm_rcc_init();pwm_pin_init();pwm_cnt_irq_init();pwm_tim_init();
}int32_t get_pwm_period(void){return (int32_t)((SYS_FRQ / PWM_FRQ ) - 1);
}void pwm_reset_duty_cnt(uint8_t index, int16_t cnt){if(cnt <= 0){cnt = get_pwm_period()/2;}switch(index){case 1:TIM1->CCR1 = (uint16_t)cnt;break;case 2:TIM1->CCR2 = (uint16_t)cnt;break;case 3:TIM1->CCR3 = (uint16_t)cnt; break;}
}void pwm_disable(void){TIM_CtrlPWMOutputs(TIM1, DISABLE);
}void pwm_enable(void){TIM_CtrlPWMOutputs(TIM1, ENABLE);
}
以上代码主要实现以下几个功能;
- IM1定时器时钟,使用中央对齐模式1,则会产生上溢信号;
- PWM模式设置为
TIM_OCMode_PWM1
; - 加入了死区;
- 占空比 50%;
具体如下图所示;
参考
http://www.stmcu.org.cn/module/forum/thread-613602-1-1.html
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