CCS/LAUNCHXL-CC26X2R1: Calibration of the XOSC_LF clock after boot up

Hi Shiv, 

Assigning an expert to comment. 

Thanks, 
Elin

Hi Shiv,

Could you elaborate on what the idea behind the implementation are, are you trying to calibrate the XOSC_LF, in that case, what are you calibrating it against?

Also, why are do you setup to use RCOSC_LF when you seem to have the XOSC_LF mounted and running?

Hi M-W,

 The system starts up with the RCOSC_LF clock. Because of which first we let it synchronize with TDC reference clock. And then I am trying to switch from RCOSC_LF to the XOSC_LF as SCLK_LF source in the application. 

So, I have perform the following steps in the BIM :

• SET_CCFG_MODE_CONF_SCLC_LF_OPTION 0x03  for LF RCOSC in the ccfg area
• Set calibrateRCOSC_LF as false in the static Power configuration structure. As there were no structure in the BIM, I have added the files to access the static Power configuration structure and initialize the power manager
• Request XOSC_LF to use TDC Reference clock
• Then wait for  TDC reference clock get ready
• Switch the LF Clock from RCOSC_LF to the XOSC_LF as SCLK_LF source.

These steps are working fine in the debugging session but after the hard reset AUX_SYSIF_TDCREFCLKCTL_ACK is not able to set.

Regards,

Shiv

Hi Shiv,

I don't see why you can't simply set SET_CCFG_MODE_CONF_SCLC_LF_OPTION to always use the XOSC_LF and don't mind the RCOSC_LF when in the BIM? Also, are you doing anything related to precise timing in the BIM today that requires the calibration prior to running the application (which likely is already setup to perform this)?

 As for your TDC code, could you share the full code you use to set it up (with that I mean i small example snippet that I could run)?

Hi M-W,

There is limitation for our project. Due to the power constraint we have to use RCOSC_LF at system startup. And then switch from RCOSC_LF to XOSC_LF as SCLK_LF source.

The whole sequence is called just after boot up in the BIM. As I meniton I have added the board specific files for initializing the power manager with static power configuration structure (i.e. turn off the calibrateRCOSC_LF ).So, after boot up process, Board_initGeneral function is called which initialize the power manager (power_init()). After which all the steps are performed in sequence as mention in previous comment.And I have remove the power manager initialization(power_init()) from the application, as we are initializing that in the BIM.

int main(void)
{
    Board_initGeneral();

    RequestXoscLfUsingTdcRef();
    usleep(20000);

    while (IsTdcRefClkReady() == 0)
    {
        usleep(10000);
    }

I am getting stuck in the while loop, as AUX_SYSIF_TDCREFCLKCTL_ACK is not able to set. For RequestXoscLfUsingTdcRef() and IsTdcRefClkReady() code snippets:

RequestXoscLfUsingTdcRef( void )
{
    // Select XOSC_LF as TDC_REF clock source
    HWREGH( AUX_DDI0_OSC_BASE + DDI_O_SET + DDI_0_OSC_O_CTL0 ) = ( 3 << DDI_0_OSC_CTL0_ACLK_REF_SRC_SEL_S );

    // Must sync twice to let TDC_REF setting propagate before requesting it
    HWREG( AON_RTC_BASE + AON_RTC_O_SYNC );
    HWREG( AON_RTC_BASE + AON_RTC_O_SYNC ) = 1 ;
    HWREG( AON_RTC_BASE + AON_RTC_O_SYNC );

    // Enable the TDC_REF clock request
    HWREG( AUX_SYSIF_BASE + AUX_SYSIF_O_TDCREFCLKCTL ) = AUX_SYSIF_TDCREFCLKCTL_REQ ;
}

IsTdcRefClkReady( void )
{
    if ( HWREG( AUX_SYSIF_BASE + AUX_SYSIF_O_TDCREFCLKCTL ) & AUX_SYSIF_TDCREFCLKCTL_ACK ) {
        return ( 1 );
    }
    return ( 0 );
}

Can you check and let us know the behavior why these steps are working fine in the debugging session but after the hard reset AUX_SYSIF_TDCREFCLKCTL_ACK is not able to set. 

Regards,

Shiv

Hi Shiv,

I will take a look at the TDC part and get back to you.

The rest of your "BIM" is however still confusing. First of all, the BIM as supplied by TI does not run either TI-RTOS or NoRTOS which means you can't use for example the PIN driver or the Power driver/manager.

As you are doing this, I will only assume that you are running your own bootloader that is based on either NoRTOS or TI-RTOS. In that case, how do you branch to the application? As you say that you later will not do any power initialization in the application because you did it in the BIM I could only assume you are not jumping into the reset routine? Typically the bootloader and application is decoupled in this way, which means you need to do the "init" on both sides (if you also do it in BIM) as they do not share state.

What I'm trying to understand is what you do in the bootloader that require you to calibrate the RCOSC_LF. Also, if you are already using TI-RTOS / NoRTOS (as you claim to have added int he power manager) , why do you not use the calibration routine that is already included as part of the power manager?

Hi M-W,

" In that case, how do you branch to the application? As you say that you later will not do any power initialization in the application because you did it in the BIM I could only assume you are not jumping into the reset routine? Typically the bootloader and application is decoupled in this way, which means you need to do the "init" on both sides (if you also do it in BIM) as they do not share state. "

I have added the library files for the NoRTOS in the BIM because of which we are able to initialize the Power Manager. We directly jump to the known address of the Application because of which I think we don't need to again initialize the power manager. And why does it have to run the reset routine, when we are directly jumping the Application from the main() of BIM with the known address of the Application?

Right now we are not using any precise timing for anything in the BIM. But it can be required in the future. So, we are doing all initialization part in the BIM and later using it in the Application.

Regards,
Shiv