TI-RTOS-MCU: PWM driver / example

Hi, Arshiya,

What device are you working on? If you can specify the SoC, we'll get the right expert to help  you.

Rex

I am working on Beaglebone Black - the SoC on it is AM335x

Hi, Arshiya,

Ok. I'll move the thread to Sitara Forum. Expert in Sitara team will help you.

Rex

Sure, Thank you so much! How long before I can expect a response from that team?

Hi, 

Just wanted to check the status of response for my concern? This is kind of urgent, can you please let me know when can I expect a response?

Hi Frank,

Thank you for your response.

I am trying to add TI RTOS support to the epwm starterware example to test the example on BeagleBone Black according to the discussion on this thread:  https://e2e.ti.com/support/processors/f/791/t/887926

I am following the readme.txt file in starterware/dcan folder to setup the project. However the board I am trying to use is bbbAM335x (BEAGLEBONEBLACK) and the readme.txt file has instructions only for evmAM335x or evmAM437x.

I am able to run the script for AM335x, however I am not able to detect the epwm project. I have attached a screenshot for your reference. 

Can I use the same procedure for my EVM, if not is there a guide for bbbAM335x EVM to add TI RTOS Support for the Starterware examples?

Thank you.

Arshiya Tabassum

Hi Frank,

Thank you for the reply. 

I tried used the method described in the section: "Building DCAN Loopback Example for RTOS - Using Makefile". I am getting errors. I tried both the commands you mentioned above. Please see the screenshots below.

I tried changing the PLATFORM and BOARD to seee if that works. Still got the same issue.

Thank you.

Arshiya Tabassum

Hi Arshiya,

It works for me. I installed AM335x PRSDK 6.3.0.106 to c:\ti

 c:\ti_am335x_06_03_00_106\pdk_am335x_1_0_17\packages
# pdksetupenv.bat
***************************************************
Environment Configuration:
***************************************************
    SDK_INSTALL_PATH        : c:/ti_am335x_06_03_00_106
    PDK_INSTALL_PATH        : c:/ti_am335x_06_03_00_106/pdk_am335x_1_0_17/packages
    GMAKE_INSTALL_PATH      : c:/ti_am335x_06_03_00_106/xdctools_3_55_02_22_core
    PDK_SOC                 : am335x
    PDK_VERSION             : 1_0_17
    RULES_MAKE              : c:/ti_am335x_06_03_00_106/pdk_am335x_1_0_17/packages/ti/build/Rules.make
***************************************************

Next:

# cd ti\starterware
# gmake epwm_app_haptics_motor PLATFORM=am335x-evm BOARD=AM335x PROFILE=release

My build log is attached.

Regards,
Frank

0211.build_log.txt

Hi Frank, 

Thank you for trying to build from your end.

However, you have used am335x-evm as your board and I am trying to use bbbAM335x as the board for which it is not able to recognize the example project.

Please guide me keeping in consideration my setup:

Board: BEAGLEBONE BLACK WIRELESS

(bbbAM335x)

Processor: AM335x

Thank you,

Arshiya Tabassum

Also, I found this documentation and thee is a PWM.h file by TI RTOS. Can I use this for my PWM implementation?PWM (1).h

And there is a thread where someone is using the PWM : https://e2e.ti.com/support/legacy_forums/embedded/tirtos/f/355/t/559330?TI-RTOS-PWM-Drivers-Closing-a-PWM-handle-does-not-correctly-turn-off-PWM-generators-outputs-

Can I use the same library if available?

http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/tirtos/2_14_04_31/exports/tirtos_full_2_14_04_31/docs/doxygen/html/_p_w_m_8h.html

Arshiya,

I'm completely unfamiliar with this TI-RTOS driver, and I'm unable to locate this header file anywhere in PRSDK 6.3.0.106, including anywhere in BIOS 6.76.03.01. It appears it's supported for Tiva-C, not AM335x.

I've looped in a colleague who may have more information.

Regards,
Frank

Hi Frank,

Thank you for the detailed explanation. That part is clear now.

So, to re-iterate, I can use the starterware APIs for ePWM as they are ( located here: startware/include/epwm.h) for implementing the PWM in my RTOS project. 

You'll need to account for any platform-specific differences between the supported platform and BBB. This part is up you.

By this, I can think of the board specific files I need to change according to my board. What else might come into picture from your understanding just to not miss out on anything?

Thank you,

Arshiya Tabassum

Sure, thank you for the clarification Todd! 

Hi Arshiya,

Arshiya Tabassum said:

I can use the starterware APIs for ePWM as they are ( located here: startware/include/epwm.h) for implementing the PWM in my RTOS project.

Yes.

Arshiya Tabassum said:

What else might come into picture from your understanding just to not miss out on anything?

I can't of anything else we haven't already covered in this thread.

Regards,
Frank

Hi Frank,

As mentioned earlier, I am using AM335x in my project. I am trying to utilize the EHRPWM2A (P8 header on BeagleBone Black)

I am using the steps mentioned in one the API for pwm initialization as follows:

uint32_t EPWMAppInit(epwmAppPwmObj_t *pPwm)
{
    int32_t status = S_PASS;
	uint16_t ePwmSubmodType = PINMUX_SS_PWMSS_EHRPWM0;

    /* Clock Configuration  */
    status = PRCMModuleEnable(CHIPDB_MOD_ID_PWMSS, pPwm->instNum, 0);
    if(S_PASS != status)
    {
        CONSOLEUtilsPrintf("\n FAILURE!!! Clock Configuration failed !\n");
    }
    else
    {
        /* PinMux Configuration */
        status = PINMUXModuleConfig(CHIPDB_MOD_ID_PWMSS, pPwm->instNum, &ePwmSubmodType);
        if(S_PASS != status)
        {
            CONSOLEUtilsPrintf("\n FAILURE!!! Pin Muxing failed !\n");
        }
        else
        {
            /* Get the functional clock value of PWMSS */
            /* TODO: This value has to be provided by the PRCM data base */
            pPwm->funcClk = SOC_EHRPWM_2_MODULE_FREQ;

            /* Enable clocks for EPWM module inside the PWM sub system. */
            EHRPWMClockEnable(pPwm->instAddr);

            /* Enable Time base clock for PWMSS module */
            SOCCtrlPwmssTimebaseClkEnable(pPwm->instNum);

            /* EPWM channel configuration */
            EpwmAppPwmCfg(pPwm);
        }
    }

    return status;
}

/* Get the functional clock value of PWMSS */
            /* TODO: This value has to be provided by the PRCM data base */
            pPwm->funcClk = SOC_EHRPWM_2_MODULE_FREQ;

What does it mean by getting the value from PWMSS? Is it from the PRCMModuleEnable()?

Thank you,
Arshiya 

Hi Frank,

I am using the haptics-motor example to create the sequence of pwm initialization, please let me know if this example can be followed for general guidance. I wanted to understand the flow for opening the PWM like other peripherals I2C, SPI etc.

I look forward to your response.

Thank you,

Arshiya Tabassum