AM2434: ECAP - time latch problem

Tool/software:

Hi,

I'm trying to use ECAP (peripheral #1, not #0) on my board & project.

Unlike the sdk example project - I do not use the ISR function.

I tried to make some sanity testing and I'm getting odd results unlike your example output.

I've configured pin C17(MCAN1_TX)  to mode 2 - APWM_ECAP1.

I'm using a signal generator to produce a 1kHz Square Pulse at both 50% and 25% Duty Cycle (2 different test cases).

This is my configuration code:

    /* Disable CAP1-CAP4 register loads */
    ECAP_captureLoadingDisable(gEcapBaseAddr);

    /* Configure eCAP */
    ECAP_counterControl(gEcapBaseAddr, ECAP_COUNTER_STOP);
    /* Enable capture mode */
    ECAP_operatingModeSelect(gEcapBaseAddr, ECAP_CAPTURE_MODE);

    /* One shot mode, stop capture at event 4 */
    ECAP_oneShotModeConfig(gEcapBaseAddr, ECAP_CAPTURE_EVENT4_STOP);
//    ECAP_continuousModeConfig(gEcapBaseAddr);

    /* Set polarity of the events to rising, falling, rising, falling edge */
    ECAP_captureEvtPolarityConfig(gEcapBaseAddr,
                                 ECAP_CAPTURE_EVENT_RISING,
                                 ECAP_CAPTURE_EVENT_FALLING,
                                 ECAP_CAPTURE_EVENT_RISING,
                                 ECAP_CAPTURE_EVENT_FALLING);

    /* Set capture in time difference mode */
    ECAP_captureEvtCntrRstConfig(gEcapBaseAddr,
                                 ECAP_CAPTURE_EVENT_RESET_COUNTER_RESET,
                                 ECAP_CAPTURE_EVENT_RESET_COUNTER_RESET,
                                 ECAP_CAPTURE_EVENT_RESET_COUNTER_RESET,
                                ECAP_CAPTURE_EVENT_RESET_COUNTER_RESET);

    ECAP_counterControl(gEcapBaseAddr, ECAP_COUNTER_FREE_RUNNING);
    ECAP_syncInOutSelect(gEcapBaseAddr, ECAP_ENABLE_COUNTER, ECAP_SYNC_IN);

    /* Enable eCAP module */
    ECAP_captureLoadingEnable(gEcapBaseAddr);

However - I'm not getting the right results when using:

        ECAP_oneShotReArm(gEcapBaseAddr);

####   Assume there is a delay here for the registers to load ###

        /* Read Counter values and print for last iteration. */
        cap1Count = ECAP_timeStampRead(gEcapBaseAddr, ECAP_CAPTURE_EVENT_1);
        cap2Count = ECAP_timeStampRead(gEcapBaseAddr, ECAP_CAPTURE_EVENT_2);
        cap3Count = ECAP_timeStampRead(gEcapBaseAddr, ECAP_CAPTURE_EVENT_3);
        cap4Count = ECAP_timeStampRead(gEcapBaseAddr, ECAP_CAPTURE_EVENT_4);

cap1Count sometimes shows unreasonable values like 200,000,000.

Also I would expect the values of the rising edges/falling edges would be equal in case of 50% PWM - which they aren't,

In the case of 25% - there is no data consistency much like in the 50% DC case.

Also note -> pin D18 for APWM_ECAP0 is used for the Sigma Delta clock.

Thanks in advance