CCS/MSP432P401R: Issue with integration of tachometers using MSP432SDK in RTOS (Posix thread)

Hello Min Min,

Apologize for the delay in response!

Myo Min Min Paing said:

Due to incompatibility issue, I redirected implementation to MSP432SDK library. But the library only defines one pin only in each timer (unlike the previous library).

From this statement I understand that you are currently using the TI-Drivers library in SimpleLink MSP432P4 SDK (./source/ti/drivers/).

Myo Min Min Paing said:

I refer to the program in this link and modify from one input capture to two. http://dev.ti.com/tirex/explore/node?node=AJnos0yvE0MmjXvUYxHYhQ__z-lQYNj__LATEST

So looks like you are using the Capture TI-Driver (./source/ti/drivers/Capture.c). According to the TI-Driver documentation of Capture module for MSP432P4 MCU, it looks like for each instance of the capture driver only one capturePort definition is allowed.

Myo Min Min Paing said:

Then I changed to different pin on the other timerA1. It is also not working; only one side is working and preempting other side resulting issue during integration.

According to the documentation this should work.

Capture_open() should be called once per capture instance. In your case since you need two capture pins, you will have to call Capture_open() twice. Are you doing this?

Also looks like you are using an older version of the SDK. Please upgrade to the 3.30 version as it comes with support for SysConfig. SysConfig makes the configuration of the TI-Drivers very easy when compared to updating the older board files (board.h, MSP_EXP432P401R.c and MSP_EXP432P401R.h).

The SysConfig Basics SimpleLink Academy lab will provide a good overview on using SysConfig.

Thanks,

Sai

Hi fellow RSLK enthusiast, I also wanted to use the TI-RTOS with my RSLK (I really wanted to learn ti-rtos).

I managed to get it working by 

a) configuring the syscfg file to use P10.4 pin with timer 3.

b) excluding the syscfg file from the build and hacking the generated ti_drivers_config.c file and manually including them (I believe this is quite normal to do this).... 

const CaptureMSP432_HWAttrs captureMSP432HWAttrs[CONFIG_CAPTURE_COUNT] = {
    /* CONFIG_CAPTURE_TACHO_0 */
    {
        .timerBaseAddress = TIMER_A3_BASE,
        .clockSource      = TIMER_A_CLOCKSOURCE_SMCLK,
        .clockDivider     = TIMER_A_CLOCKSOURCE_DIVIDER_1,
        .capturePort      = CaptureMSP432_P10_4_TA3,
        .intPriority      = (~0),
    },
    {
        .timerBaseAddress = TIMER_A3_BASE,
        .clockSource      = TIMER_A_CLOCKSOURCE_SMCLK,
        .clockDivider     = TIMER_A_CLOCKSOURCE_DIVIDER_1,
        .capturePort      = CaptureMSP432_P10_5_TA3,
        .intPriority      = 2,
    },
};

/*
 *  ======== Capture_config ========
 */
const Capture_Config Capture_config[CONFIG_CAPTURE_COUNT] = {
    /* CONFIG_CAPTURE_TACHO_0 */
    {
        .fxnTablePtr = &CaptureMSP432_captureFxnTable,
        .object = &captureMSP432Objects[CONFIG_CAPTURE_TACHO_0],
        .hwAttrs = &captureMSP432HWAttrs[CONFIG_CAPTURE_TACHO_0]
    },
    {
         .fxnTablePtr = &CaptureMSP432_captureFxnTable,
         .object = &captureMSP432Objects[CONFIG_CAPTURE_TACHO_N],
         .hwAttrs = &captureMSP432HWAttrs[CONFIG_CAPTURE_TACHO_N]
    },
};

c) fixed up the define CaptureMSP432_P10_5_TA3 (it has an obvious bug)

d) when I actually go to open the capture, my code looks like this....

int tachoOpen()
{
    Capture_Params    params;
    Capture_Params_init(&params);
    params.mode  = Capture_RISING_EDGE;
    params.callbackFxn = TA2_0_Callback;
    params.periodUnit = Capture_PERIOD_COUNTS;
    _tachoHandle0 = Capture_open(CONFIG_CAPTURE_TACHO_0, &params);

    if (_tachoHandle0 == NULL) {
        System_abort("Error Initializing capture P10.4 (right)\n");
        return -1;
    }

    TimerMSP432_HWAttrs const *hwAttrs = _tachoHandle0->hwAttrs;
    TimerMSP432_freeTimerResource(hwAttrs->timerBaseAddress);

    params.callbackFxn = TA2_N_Callback;
    _tachoHandleN = Capture_open(CONFIG_CAPTURE_TACHO_N, &params);

    if (_tachoHandleN == NULL) {
        System_abort("Error Initializing capture P10.5 (left)\n");
        return -1;
    }

    return 0;
}

int tachoStart()
{
    int32_t status = Capture_start(_tachoHandle0);
    if (status == Capture_STATUS_ERROR) {
        return -1;
    }
    status = Capture_start(_tachoHandleN);
    if (status == Capture_STATUS_ERROR) {
        return -1;
    }

    return 0;
}

I hope this helps (it works for me;) )

I thought I might add that if you use linear interpolation on the sin/cosine look up table, you get very good results for calculating odometry.

Can I also add that this is a fantastic little robot for all sorts of endeavours. I love the breadboard on top and the wifi interface - that means I can off load compute to my PC. Can I suggest maybe the next version includes an gyro/accelerometer so you can also do a lesson on the Kalman filter.