i.MX ProcessorsのトピックRe: Problems Setting Prescaler for PWM capture

Problems Setting Prescaler for PWM capture

mexp2 — Mon, 10 Jul 2023 12:00:50 GMT

We are using a PWM input to capture a external frequency of a tacho.

With the standard settings everything works fine but when i apply a prescaler during initialization

pwmConfig.prescale = kPWM_Prescale_Divide_64;

or by setting it via

void PWM_SetClockMode

the values of CVAL2 and CVAL3 are always 0x00 and the counter is not counting

My signal has a frequency of 200Hz

Re: Problems Setting Prescaler for PWM capture

Sanket_Parekh — Tue, 11 Jul 2023 08:22:43 GMT

Hi @mexp2 ,

I hope you are doing well.

Please specify which i.MX Processor is used to debug further.

Thanks & Regards,
Sanket Parekh

Re: Problems Setting Prescaler for PWM capture

mexp2 — Fri, 14 Jul 2023 08:03:50 GMT

We use the imxRT1062 with the SDK v 2.13.0

/* Read the PWM default configuration */ PWM_GetDefaultConfig(&pwmConfig); pwmConfig.reloadLogic = kPWM_ReloadImmediate; pwmConfig.pairOperation = kPWM_Independent; pwmConfig.enableDebugMode = true; /* Init the pwm */ if( PWM_Init(TACHOPUMP_PERIPHERAL, TACHOPUMP_CHANNEL, &pwmConfig) == kStatus_Fail) { PRINTF("Can't initialize PWM\n"); return; } /* Configure the capture input of the PWM for one shot polling */ pwm_input_capture_param_t captureConfig; captureConfig.captureInputSel = false; captureConfig.edge0 = kPWM_RisingEdge; captureConfig.edge1 = kPWM_RisingEdge; captureConfig.enableOneShotCapture = true; PWM_SetupInputCapture(TACHOPUMP_PERIPHERAL, TACHOPUMP_CHANNEL, TACHOPUMP_SIGNAL, &captureConfig); PWM_SetPwmLdok(TACHOPUMP_PERIPHERAL, timerBitmask, true); PWM_StartTimer(TACHOPUMP_PERIPHERAL, timerBitmask);

with this code everything works as expected, but if i add a prescaler in the configuration

pwmConfig.prescale = kPWM_Prescale_Divide_128;

the counter is not counting anymore

Re: Problems Setting Prescaler for PWM capture

RaRo — Mon, 24 Jul 2023 20:29:32 GMT

Hello @mexp2,

First of all, we apologize for the delay to answer you.

Just for double check, could you please tell us where are you placing the kPWM_Prescale_Divide_128? It might be good if you could write the pwmConfig.prescale=kPWM_Prescale_Divide_128; after pwmConfig.pairOperation=kPWM_Independent; and before PWM_Init(). Also, which clock source are you using?

Finally, could you please try to use other values of the prescaler below 64?

Best regards, Raul.

Problems Setting the Prescaler for PWM capture

coderick — Thu, 30 Oct 2025 02:04:21 GMT

你好，我也遇到了楼主同样的问题，将分频代码去掉或者设为1分频时，Counter可以正常运行，但是设置2分频或更高的分频时Counter就停止了，这是什么原因？

void Capture_config(void) { pwm_input_capture_param_t pwm_input_capture; gpio_pin_config_t PWM_pin_config; //初始化输入捕获管脚 IOMUXC_SetPinMux(PWM2_PWMA03_IOMUXC, 0U); //设置外部引脚的复用功能 IOMUXC_SetPinConfig(PWM2_PWMA03_IOMUXC, PWMC_INPUT_PAD_CONFIG_DATA); //设置引脚的 pad 属性 PWM_pin_config.direction = kGPIO_DigitalInput; PWM_pin_config.interruptMode = kGPIO_NoIntmode; GPIO_PinInit(PWM2_PWMA03_GPIO, PWM2_PWMA03_GPIO_PIN, &PWM_pin_config); //初始化输入捕获配置参数 pwm_input_capture.captureInputSel = false; pwm_input_capture.edge0 = kPWM_RisingEdge; //pwm_input_capture.edge1 = kPWM_FallingEdge; pwm_input_capture.enableOneShotCapture = false; //pwm_input_capture.edgeCompareValue = 10; //当captureInputSel为FALSE时，此处设值无意义 pwm_input_capture.fifoWatermark = 0; PWM_SetupInputCapture(PI_PWM_BASEADDR, kPWM_Module_3, kPWM_PwmA, &pwm_input_capture); //开启捕获中断 //set_IRQn_Priority(PWM2_3_IRQn,Group4_PreemptPriority_0, Group4_SubPriority_0);//设置中断优先级 //PWM_EnableInterrupts(PI_PWM_BASEADDR, kPWM_Module_3, kPWM_CaptureA0InterruptEnable| kPWM_CaptureA1InterruptEnable ); PWM_EnableInterrupts(PI_PWM_BASEADDR, kPWM_Module_3, kPWM_CaptureA0InterruptEnable ); EnableIRQ(PWM2_3_IRQn); } /** * @brief 初始化 PWM 配置参数 * @retval 无 */ void PWM_config(void) { pwm_config_t pwmConfig;//定义pwm 配置结构体 PWM_Deinit(PI_PWM_BASEADDR, kPWM_Module_3); /*设置AHB总线时钟和IP总线时钟*/ CLOCK_SetDiv(kCLOCK_IpgDiv, 0x3); /* Set IPG PODF to 3, divede by 4 */ /*设置pwm 错误输入为高电平，表示没有错误，只有当pwm 没有错误输入或者禁止错误检测才能正常输出pwm波*/ XBARA_Init(XBARA1); XBARA_SetSignalsConnection(XBARA1, kXBARA1_InputLogicHigh, kXBARA1_OutputFlexpwm1Fault0); XBARA_SetSignalsConnection(XBARA1, kXBARA1_InputLogicHigh, kXBARA1_OutputFlexpwm1Fault1); XBARA_SetSignalsConnection(XBARA1, kXBARA1_InputLogicHigh, kXBARA1_OutputFlexpwm1234Fault2); XBARA_SetSignalsConnection(XBARA1, kXBARA1_InputLogicHigh, kXBARA1_OutputFlexpwm1234Fault3); PWM_GetDefaultConfig(&pwmConfig); pwmConfig.reloadLogic = kPWM_ReloadPwmFullCycle; //新值在上一个pwm周期输出结束之后加载到缓冲寄存器中 pwmConfig.pairOperation = kPWM_Independent; // 工作在独立模式 pwmConfig.clockSource = kPWM_BusClock; pwmConfig.enableDebugMode = true; // 使能DebugMode pwmConfig.prescale = kPWM_Prescale_Divide_128; //1320000000/128/65535=16Hz=PWM最小频率 //初始化 PWM 并且判断初始化是否成功 if (PWM_Init(PI_PWM_BASEADDR, kPWM_Module_3, &pwmConfig) == kStatus_Fail) { PRINTF("PWM initialization failed\n"); } Capture_config(); PWM_SetPwmLdok(PI_PWM_BASEADDR,kPWM_Control_Module_3 , true); PWM_StartTimer(PI_PWM_BASEADDR, kPWM_Control_Module_3 ); }

Re: Problems Setting Prescaler for PWM capture

isharaby — Sat, 15 Nov 2025 16:00:04 GMT

Hello,

I've encountered the same issue,
when configuring the any of the four PWM peripherals clock perscaler with values other than kPWM_Prescale_Divide_1 , the counter of the selected PWM peripheral doesn't work at all.

I'm using the imxrt1062 processor and MCUXpresso IDE v11.9.1

I hope, you can support me as soon as possible.
And, here is a snippet of my code where I configure and initialize the pwm peripherals.

static void pwm_init(void)

{

pwm_config_t pwmConfig;

pwm_input_capture_param_t captureConfig;

pwm_fault_param_t faultConfig;

/* Read the PWM default configuration */

PWM_GetDefaultConfig(&pwmConfig);

pwmConfig.clockSource = kPWM_BusClock;

pwmConfig.prescale = kPWM_Prescale_Divide_2;

pwmConfig.pairOperation = kPWM_Independent;

pwmConfig.initializationControl = kPWM_Initialize_LocalSync;

pwmConfig.reloadLogic = kPWM_ReloadImmediate;

pwmConfig.reloadSelect = kPWM_LocalReload;

pwmConfig.reloadFrequency = kPWM_LoadEveryOportunity;

pwmConfig.forceTrigger = kPWM_Force_LocalSync;

pwmConfig.enableDebugMode = true;

PWM_Init(PWM1_BASEADDR, kPWM_Module_3, &pwmConfig);

PWM_Init(PWM2_BASEADDR, kPWM_Module_3, &pwmConfig);

PWM_Init(PWM3_BASEADDR, kPWM_Module_1, &pwmConfig);

PWM_Init(PWM4_BASEADDR, kPWM_Module_1, &pwmConfig);

// fault configuration

PWM_FaultDefaultConfig(&faultConfig);

/* Sets up the PWM fault protection */

PWM_SetupFaults(PWM1_BASEADDR, kPWM_Fault_0, &faultConfig);

PWM_SetupFaults(PWM1_BASEADDR, kPWM_Fault_1, &faultConfig);

PWM_SetupFaults(PWM1_BASEADDR, kPWM_Fault_2, &faultConfig);

PWM_SetupFaults(PWM1_BASEADDR, kPWM_Fault_3, &faultConfig);

/* Set PWM fault disable mapping for submodule 0/1/2 */

PWM_SetupFaultDisableMap(PWM1_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM1_BASEADDR, kPWM_Module_1, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM1_BASEADDR, kPWM_Module_2, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM1_BASEADDR, kPWM_Module_3, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

/* Sets up the PWM fault protection */

PWM_SetupFaults(PWM2_BASEADDR, kPWM_Fault_0, &faultConfig);

PWM_SetupFaults(PWM2_BASEADDR, kPWM_Fault_1, &faultConfig);

PWM_SetupFaults(PWM2_BASEADDR, kPWM_Fault_2, &faultConfig);

PWM_SetupFaults(PWM2_BASEADDR, kPWM_Fault_3, &faultConfig);

/* Set PWM fault disable mapping for submodule 0/1/2 */

PWM_SetupFaultDisableMap(PWM2_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM2_BASEADDR, kPWM_Module_1, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM2_BASEADDR, kPWM_Module_2, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM2_BASEADDR, kPWM_Module_3, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

/* Sets up the PWM fault protection */

PWM_SetupFaults(PWM3_BASEADDR, kPWM_Fault_0, &faultConfig);

PWM_SetupFaults(PWM3_BASEADDR, kPWM_Fault_1, &faultConfig);

PWM_SetupFaults(PWM3_BASEADDR, kPWM_Fault_2, &faultConfig);

PWM_SetupFaults(PWM3_BASEADDR, kPWM_Fault_3, &faultConfig);

/* Set PWM fault disable mapping for submodule 0/1/2 */

PWM_SetupFaultDisableMap(PWM3_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM3_BASEADDR, kPWM_Module_1, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM3_BASEADDR, kPWM_Module_2, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM3_BASEADDR, kPWM_Module_3, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

/* Sets up the PWM fault protection */

PWM_SetupFaults(PWM4_BASEADDR, kPWM_Fault_0, &faultConfig);

PWM_SetupFaults(PWM4_BASEADDR, kPWM_Fault_1, &faultConfig);

PWM_SetupFaults(PWM4_BASEADDR, kPWM_Fault_2, &faultConfig);

PWM_SetupFaults(PWM4_BASEADDR, kPWM_Fault_3, &faultConfig);

/* Set PWM fault disable mapping for submodule 0/1/2 */

PWM_SetupFaultDisableMap(PWM4_BASEADDR, kPWM_Module_0, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM4_BASEADDR, kPWM_Module_1, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM4_BASEADDR, kPWM_Module_2, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

PWM_SetupFaultDisableMap(PWM4_BASEADDR, kPWM_Module_3, kPWM_PwmA, kPWM_faultchannel_0, kPWM_FaultDisable_0 | kPWM_FaultDisable_1 | kPWM_FaultDisable_2 | kPWM_FaultDisable_3);

/* Configure the capture input of the PWM for one shot polling */

captureConfig.captureInputSel = true;

captureConfig.edge0 = kPWM_RiseAndFallEdge;

captureConfig.edge1 = kPWM_Disable;

captureConfig.enableOneShotCapture = false;

captureConfig.edgeCompareValue = 1;

PWM_SetupInputCapture(PWM1_BASEADDR, kPWM_Module_3, kPWM_PwmA, &captureConfig);

PWM_SetupInputCapture(PWM2_BASEADDR, kPWM_Module_3, kPWM_PwmA, &captureConfig);

PWM_SetupInputCapture(PWM3_BASEADDR, kPWM_Module_1, kPWM_PwmA, &captureConfig);

PWM_SetupInputCapture(PWM4_BASEADDR, kPWM_Module_1, kPWM_PwmA, &captureConfig);

PWM_SetPwmLdok(PWM1_BASEADDR, kPWM_Control_Module_3, true);

PWM_SetPwmLdok(PWM2_BASEADDR, kPWM_Control_Module_3, true);

PWM_SetPwmLdok(PWM3_BASEADDR, kPWM_Control_Module_1, true);

PWM_SetPwmLdok(PWM4_BASEADDR, kPWM_Control_Module_1, true);

PWM_StartTimer(PWM1_BASEADDR, kPWM_Control_Module_3);

PWM_StartTimer(PWM2_BASEADDR, kPWM_Control_Module_3);

PWM_StartTimer(PWM3_BASEADDR, kPWM_Control_Module_1);

PWM_StartTimer(PWM4_BASEADDR, kPWM_Control_Module_1);

}