要求得到下列波形，死区时间为1us，CH1，CH2，CH3之间的相位差为3us，频率为50KHz
main.c
/*********************************************
标题：定时器输出带有死区时间的PWM波形
软件平台：MDK-ARM Standard Version4.70
硬件平台：stm32f4-discovery
主频：168M
Periph_Driver_version: V1.0.0
描述：用一个定时器(TIM1)，输出带有死区时间的PWM波形，要求：死区时间为1us，CH1，CH2，CH3之间的相位差为3us，频率为50KHz
代码参考自STM32F4-Discovery_FW_V1.1.0\Project\Peripheral_Examples\TIM_ComplementarySignals
author：大舟
data：2013-04-15
**********************************************/
#include "stm32f4_discovery.h"
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_BDTRInitTypeDef TIM_BDTRInitStructure;
uint16_t TimerPeriod = 0;
uint16_t Channel1Pulse = 0, Channel2Pulse = 0, Channel3Pulse = 0;
/* Private function prototypes */
void TIM_Config(void);
int main(void)
{
/*!< At this stage the microcontroller clock setting is already configured,
this is done through SystemInit() function which is called from startup
file (startup_stm32f4xx.s) before to branch to application main.
To reconfigure the default setting of SystemInit() function, refer to
system_stm32f4xx.c file
*/
/* TIM1 Configuration */
TIM_Config();
/* -----------------------------------------------------------------------
1/ Generate 3 complementary PWM signals with 3 different duty cycles:
In this example TIM1 input clock (TIM1CLK) is set to 2 * APB2 clock (PCLK2),
since APB2 prescaler is different from 1 (APB2 Prescaler = 2, see system_stm32f4xx.c file).
TIM1CLK = 2 * PCLK2
PCLK2 = HCLK / 2
=> TIM1CLK = 2*(HCLK / 2) = HCLK = SystemCoreClock
To get TIM1 counter clock at 168 MHz, the prescaler is computed as follows:
Prescaler = (TIM1CLK / TIM1 counter clock) - 1
Prescaler = (SystemCoreClock / 168 MHz) - 1 = 0
The objective is to generate PWM signal at 17.57 KHz:
- TIM1_Period = (SystemCoreClock / 17570) - 1
To get TIM1 output clock at 17.57 KHz, the period (ARR) is computed as follows:
ARR = (TIM1 counter clock / TIM1 output clock) - 1 = 9561
The Three Duty cycles are computed as the following description:
TIM1 Channel1 duty cycle = (TIM1_CCR1/ TIM1_ARR)* 100 = 50%
TIM1 Channel2 duty cycle = (TIM1_CCR2/ TIM1_ARR)* 100 = 25%
TIM1 Channel3 duty cycle = (TIM1_CCR3/ TIM1_ARR)* 100 = 12.5%
The Timer pulse is calculated as follows:
- TIM1_CCRx = (DutyCycle * TIM1_ARR)/ 100
2/ Insert a dead time equal to (11/SystemCoreClock) ns //这句不对，示波器里观测也不对，不是这样算的。
正确的deadtime的计算方法（经理论与示波器测试成功）
TIM_BDTRInitStructure.TIM_DeadTime=255 //这句设定的就是寄存器TIMx_BDTR的后8位，即DTG[7:0],所以最大值为255
从下面的代码中的“第五步”中，实际上就相当于TIM1->BDTR=0x71FF;
查看"STM32中文参考手册2009.pdf"的TIMx_BDTR(第248页)，列寄存器TIMx_BDTR的后8位如下：
位7:0 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 = 1/168us(频率为168M)，可能的死区时间DT为：
0到756ns， 若步长时间Tdtg为1/168us；
762ns到1512ns， 若步长时间Tdtg为2/168us；
1524ns到3us， 若步长时间Tdtg为8/168us；
3048ns到6us， 若步长时间Tdtg为16/168us；
计算
这里要求设置deadtime为1us，落在区间"762ns到1512ns"，所以选择公式“DTG[7:5]=10x => DT=(64+DTG[5:0])×Tdtg，Tdtg=2×Tdts；”
列方程：(64+x)×2/168us = 1us；得x=20。所以DTG[5:0]=010100；推出DTG[7:0]=10010100=0x94。所以TIM_DeadTime=0x94。
3/ Configure the break feature, active at High level, and using the automatic
output enable feature
4/ Use the Locking parameters level1.
5/ 这里要求3个通道的波形不是对齐的，所以必须设定为TIM_OCMode_Toggle模式，这样，ARR得走两趟才是一个周期，
CCR1(TIM_Pulse)、CCR2、CCR3不同，则触发的点也不同，即错开了相位。
注意，不管TIM_Pulse为什么值，占空比都是50%。因为ARR走一趟才取反一次。
6/ 要求pwm输出频率为50KHz。所以ARR=(SystemCoreClock/100000)-1 = 1679。即对时钟进行1680分频。
7/ PWM1和PWM2的相位差为3us。计算如下
因为ARR自加1的时间为(1/168M)s，即可列方程：(1/168M)x=3us，得x=504。
即，CCR1、CCR2、CCR3之间相隔504时，PWM的相位差就为3us
Note:
SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f4xx.c file.
Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
function to update SystemCoreClock variable value. Otherwise, any configuration
based on this variable will be incorrect.
----------------------------------------------------------------------- */
/* Compute the value to be set in ARR register to generate signal frequency at 17.57 Khz */
TimerPeriod = (SystemCoreClock / 100000) - 1; //1679;17570 ARR=9561
/* Compute CCR1 value to generate a duty cycle at 50% for channel 1 */
Channel1Pulse = 100;//= (uint16_t) (((uint32_t) 5 * (TimerPeriod - 1)) / 10);//CCR1_Val=4780，比较值
/* Compute CCR2 value to generate a duty cycle at 25% for channel 2 */
Channel2Pulse = 604;// = (uint16_t) (((uint32_t) 25 * (TimerPeriod - 1)) / 100);//CCR2_Val=2390，比较值
/* Compute CCR3 value to generate a duty cycle at 12.5% for channel 3 */
Channel3Pulse = 1108;// = (uint16_t) (((uint32_t) 125 * (TimerPeriod - 1)) / 1000);//CCR3_Val=1195，比较值
/**@step第一步配置时钟*/
/**@step第二步配置goio口*/
/**@step第三步定时器基本配置*/
/* Time Base configuration */
TIM_TimeBaseStructure.TIM_Prescaler = 0;//时钟预分频数，对168M进行1(0+1)分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//向上计数
TIM_TimeBaseStructure.TIM_Period = TimerPeriod;//自动重装载寄存器的值，ARR=9561
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //采样分频
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;//重复寄存器，用于自动更新pwm占空比
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
/**@step第四步 PWM输出配置*/
/* Channel 1, 2 and 3 Configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM1为正常占空比模式，PWM2为反极性模式
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //High为占空比高极性，此时占空比为20%；Low则为反极性，占空比为80%
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //使能该通道输出
TIM_OCInitStructure.TIM_Pulse = Channel1Pulse; //设置占空比时间，CCR1_Val=4780，占空比为4780/(9561+1)=0.5
//-------下面几个参数是高级定时器才会用到通用定时器不用配置
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable; //使能互补端输出
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High; //设置互补端输出极性
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset; //刹车之后输出状态Specifies the TIM Output Compare pin state during Idle state
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset; //刹车之后互补端输出状态
//-------
TIM_OC1Init(TIM1, &TIM_OCInitStructure);//对channel1进行配置
TIM_OCInitStructure.TIM_Pulse = Channel2Pulse;//CCR2_Val=2390，比较值
TIM_OC2Init(TIM1, &TIM_OCInitStructure);//对channel2进行配置
TIM_OCInitStructure.TIM_Pulse = Channel3Pulse;//CCR3_Val=1195，比较值
TIM_OC3Init(TIM1, &TIM_OCInitStructure);//对channel3进行配置
/**@step第五步死区和刹车功能配置,高级定时器才有的,通用定时器不用配置*/
/* Automatic Output enable, Break, dead time and lock configuration*/
TIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable; //运行模式下输出
TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable; //空闲模式下输出选择
TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_1; //锁定设置，锁定级别1
TIM_BDTRInitStructure.TIM_DeadTime = 0x94;//死区时间1us
TIM_BDTRInitStructure.TIM_Break = TIM_Break_Disable; //刹车功能使能
TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_Low; //刹车输入极性，即刹车控制引脚接GND时，PWM停止
TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable; //自动输出使能
TIM_BDTRConfig(TIM1, &TIM_BDTRInitStructure);
/* 刹车控制引脚为TIM1_BKIN pin(PB.12)，将PB12接GND，channel和其互补通道，都变为刹车后的电平，具体为0还是1，要看如下两个设置：
.TIM_OCIdleState = TIM_OCIdleState_Reset; //刹车之后，PWM通道变为0
.TIM_OCNIdleState = TIM_OCNIdleState_Reset; //刹车之后，PWM互补通道变为0
注意：如果没必要，还是不要开启刹车功能，因为会对PWM产生影响，特别是当PB12悬空时，波形将会有很大的波动。
这里不打开刹车功能，即.TIM_Break = TIM_Break_Disable;
*/
/**@step第六步使能端的打开*/
/* TIM1 counter enable */
TIM_Cmd(TIM1, ENABLE);//打开TIM1
/* Main Output Enable */
TIM_CtrlPWMOutputs(TIM1, ENABLE);//PWM输出使能,一定要记得打
while (1);
}
/**
* @brief Configure the TIM1 Pins.
* @param None
* @retval None
*/
void TIM_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOA and GPIOB clocks enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOE, ENABLE);
/* TIM1 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
/* GPIOA Configuration: Channel 1 and 3 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* GPIOA Configuration: Channel 2 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
GPIO_Init(GPIOE, &GPIO_InitStructure);
/* GPIOB Configuration: BKIN, Channel 1N, 2N and 3N as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Connect TIM pins to AF1 */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1); //引脚功能，查看readme.txt
GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource12, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1);
}
/**@end*/
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t* file, uint32_t line)
{
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
while (1)
{}
}
#endif
/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/
readme.txt
/**
@page TIM_ComplementarySignals TIM Complementary Signals example
@verbatim
******************** (C) COPYRIGHT 2011 STMicroelectronics *******************
* @file TIM_ComplementarySignals/readme.txt
* @author MCD Application Team
* @version V1.0.0
* @date 19-September-2011
* @brief Description of the TIM Complementary Signals example.
******************************************************************************
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
* TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
* DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
* FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
* CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
******************************************************************************
@endverbatim
@par Example Description
This example shows how to configure the TIM1 peripheral to generate three
complementary TIM1 signals, to insert a defined dead time value, to use the break
feature and to lock the desired parameters.
TIM1CLK is fixed to SystemCoreClock, the TIM1 Prescaler is equal to 0 so the
TIM1 counter clock used is SystemCoreClock (168 MHz).
The objective is to generate PWM signal at 17.57 KHz:
- TIM1_Period = (SystemCoreClock / 17570) - 1
The Three Duty cycles are computed as the following description:
The channel 1 duty cycle is set to 50% so channel 1N is set to 50%.
The channel 2 duty cycle is set to 25% so channel 2N is set to 75%.
The channel 3 duty cycle is set to 12.5% so channel 3N is set to 87.5%.
The Timer pulse is calculated as follows:
- ChannelxPulse = DutyCycle * (TIM1_Period - 1) / 100
A dead time equal to 11/SystemCoreClock is inserted between the different
complementary signals, and the Lock level 1 is selected.
The break Polarity is used at High level.
The TIM1 waveform can be displayed using an oscilloscope.
@par Directory contents
- TIM_ComplementarySignals/stm32f4xx_conf.h Library Configuration file
- TIM_ComplementarySignals/stm32f4xx_it.c Interrupt handlers
- TIM_ComplementarySignals/stm32f4xx_it.h Interrupt handlers header file
- TIM_ComplementarySignals/main.c Main program
- TIM_ComplementarySignals/system_stm32f4xx.c STM32F4xx system source file
@par Hardware and Software environment
- This example runs on STM32F4xx Devices Revision A.
- This example has been tested with STM32F4-Discovery (MB997) RevA and can be
easily tailored to any other development board.
- STM32F4-Discovery
- Connect the TIM1 pins to an oscilloscope to monitor the different waveforms:
- TIM1_CH1 pin (PA.08)
- TIM1_CH1N pin (PB.13)
- TIM1_CH2 pin (PE.11)
- TIM1_CH2N pin (PB.14)
- TIM1_CH3 pin (PA.10)
- TIM1_CH3N pin (PB.15)
- Connect the TIM1 break pin TIM1_BKIN pin (PB.12) to the GND. To generate a
break event, switch this pin level from 0V to 3.3V.
@par How to use it ?
In order to make the program work, you must do the following :
+ EWARM
- Open the TIM_ComplementarySignals.eww workspace
- Rebuild all files: Project->Rebuild all
- Load project image: Project->Debug
- Run program: Debug->Go(F5)
+ MDK-ARM
- Open the TIM_ComplementarySignals.uvproj project
- Rebuild all files: Project->Rebuild all target files
- Load project image: Debug->Start/Stop Debug Session
- Run program: Debug->Run (F5)
+ TASKING
- Open TASKING toolchain.
- Click on File->Import, select General->'Existing Projects into Workspace'
and then click "Next".
- Browse to TASKING workspace directory and select the project "TIM_ComplementarySignals"
- Rebuild all project files: Select the project in the "Project explorer"
window then click on Project->build project menu.
- Run program: Select the project in the "Project explorer" window then click
Run->Debug (F11)
+ TrueSTUDIO
- Open the TrueSTUDIO toolchain.
- Click on File->Switch Workspace->Other and browse to TrueSTUDIO workspace
directory.
- Click on File->Import, select General->'Existing Projects into Workspace'
and then click "Next".
- Browse to the TrueSTUDIO workspace directory and select the project "TIM_ComplementarySignals"
- Rebuild all project files: Select the project in the "Project explorer"
window then click on Project->build project menu.
- Run program: Select the project in the "Project explorer" window then click
Run->Debug (F11)
* <h3><center>© COPYRIGHT 2011 STMicroelectronics</center></h3>
*/
代码下载地址：http://download.csdn.net/detail/dazhou158/5261883