topic Re: MCXA156 PWM Capture Setup in MCX Microcontrollers

MCXA156 PWM Capture Setup

ZRay — Fri, 07 Nov 2025 02:09:08 GMT

I would like to use the PWM Capture feature.

However, there doesn't seem to be a relevant example in the SDK there is only a sample for PWM output.

I noticed there is a Capture API in the Driver, but my attempts so far have not been successful.

I would like to ask if there are any other related samples that I can refer to.

My code is as follows:

int main(void)
{
    BOARD_InitHardware();
    PRINTF("FlexPWM input capture only\r\n");

    pwm_config_t pwmConfig;
    PWM_GetDefaultConfig(&pwmConfig);
    pwmConfig.pairOperation = kPWM_Independent;
    pwmConfig.enableDebugMode = true;

    PWM_Init(BOARD_PWM_BASEADDR, kPWM_Module_0, &pwmConfig);

    // Setup Input Capture
    pwm_input_capture_param_t captureParams = {0};
    captureParams.captureInputSel = 0;
    captureParams.edge0 = kPWM_RisingEdge;
    captureParams.edge1 = kPWM_FallingEdge;
    captureParams.enableOneShotCapture = false;
    captureParams.fifoWatermark = 0;
    captureParams.edgeCompareValue = 0;
    PWM_SetupInputCapture(BOARD_PWM_BASEADDR, kPWM_Module_0, kPWM_PwmX, &captureParams);


    PWM_StartTimer(BOARD_PWM_BASEADDR, kPWM_Control_Module_0);

    while (1)
    {
        uint16_t captured_cval0 = BOARD_PWM_BASEADDR->SM[kPWM_Module_0].CVAL0;
        PRINTF("Capture Value 0 Register: %u\r\n", captured_cval0);
        uint16_t captured_cval1 = BOARD_PWM_BASEADDR->SM[kPWM_Module_0].CVAL1;
        PRINTF("Capture Value 1 Register: %u\r\n", captured_cval1);
        
        SDK_DelayAtLeastUs(100000, SDK_DEVICE_MAXIMUM_CPU_CLOCK_FREQUENCY);
    }
}

Thank you.

Re: MCXA156 PWM Capture Setup

Alice_Yang — Fri, 07 Nov 2025 06:18:54 GMT

Hello @ZRay

Thanks for your question!

You can check out the capture demo provided in the SDK.

Alice

Re: MCXA156 PWM Capture Setup

ZRay — Tue, 11 Nov 2025 06:21:52 GMT

Hi @Alice_Yang ,

Thank you for reply.

The CTimer Capture example is work, but since our CTimer is used for other purposes, we wanted to ask if there are any reference examples related to PWM Capture.

Thank you.

Re: MCXA156 PWM Capture Setup

Alice_Yang — Tue, 11 Nov 2025 09:24:36 GMT

Hello @ZRay

Thank you for your reply.

Yes, there is no dedicated PWM capture demo based on the MCXA156. However, there is a PWM capture example implemented using the SCTIMER module. You may refer to its principle and implementation as a reference for developing PWM capture functionality on FlexPWM.

https://www.nxp.com/docs/en/application-note/AN11538.zip

Alice

Re: MCXA156 PWM Capture Setup

ZRay — Wed, 19 Nov 2025 09:33:16 GMT

Hi @Alice_Yang

Thanks for info.

I figured it out.

int main(void) { BOARD_InitHardware(); PRINTF("FlexPWM input capture only\r\n"); pwm_config_t pwmConfig; PWM_GetDefaultConfig(&pwmConfig); //pwmConfig.prescale = kPWM_Prescale_Divide_1; pwmConfig.reloadLogic = kPWM_ReloadPwmFullCycle; pwmConfig.pairOperation = kPWM_Independent; pwmConfig.enableDebugMode = true; if( PWM_Init(BOARD_PWM_BASEADDR, kPWM_Module_0, &pwmConfig)== kStatus_Fail){ PRINTF("Can't initialize PWM\n"); return 0; } // Setup Input Capture pwm_input_capture_param_t captureParams = {0}; captureParams.captureInputSel = 0; captureParams.edge0 = kPWM_RisingEdge; captureParams.edge1 = kPWM_FallingEdge; captureParams.enableOneShotCapture = false; //captureParams.fifoWatermark = 0; //captureParams.edgeCompareValue = 0; PWM_SetupInputCapture(BOARD_PWM_BASEADDR, kPWM_Module_0, kPWM_PwmX, &captureParams); //PWM_SetPwmLdok(BOARD_PWM_BASEADDR, kPWM_Control_Module_0, true); PWM_StartTimer(BOARD_PWM_BASEADDR, kPWM_Control_Module_0); while (1) { uint16_t rising = BOARD_PWM_BASEADDR->SM[kPWM_Module_0].CVAL0; uint16_t falling = BOARD_PWM_BASEADDR->SM[kPWM_Module_0].CVAL1; uint16_t high = falling > rising ? falling - rising : (falling + 0x10000) - rising; PRINTF("rising: %u falling: %u high: %u\r\n",rising, falling, high); SDK_DelayAtLeastUs(100000, SDK_DEVICE_MAXIMUM_CPU_CLOCK_FREQUENCY); } }