TMS320F28388D: Watchdog Feature on CM core

Vikram Tathe

Prodigy 175 points

Part Number: TMS320F28388D

Tool/software:

Hello Vivek Singh Hareesh Janakiraman Baskaran Chidambaram Veena Kamath and Team,

We are using TMS320F28388D microcontroller. We have below queries on watchdog feature on CM core.

For watchdog, the internal oscillator frequency (INTOSC1) as a clock source is used and its value is 10 MHz. We have calculated the Watchdog Countdown Time (ms) from the predivider (WDCLK = PREDIVCLK / XX) and prescaler (PREDIVCLK = INTOSC1 / YY) configurations.
If the derived value of the Watchdog Countdown Time is 0.2048 ms and the window value is set to 10 (to be used in SysCtl_setWatchdogWindowValue(10)), then the total duration of the watchdog window would be 0.2048 ms * 10 = 2.048 ms. correct us if our understanding is wrong.
What are the units of the parameter passed to SysCtl_setNMIWatchdogPeriod(NMI_WATCHDOG_PERIOD), or is it just a numerical counter value? If it is only a counter value, then if we pass NMI_WATCHDOG_PERIOD = 10, will the set NMI Watchdog Period be calculated as 0.2048 ms * 10 = 2.048 ms?
When NMI is enabled on the CM core and not handled (by not calling SysCtl_clearWatchdogStatus() and SysCtl_clearAllNMIFlags()), after the NMI_WATCHDOG_PERIOD expires, the watchdog overflow will trigger an NMI, which will eventually reset CM core.
After the CM core resets due to a watchdog overflow, does CPU1 need to explicitly call the Device_bootCM() function to bring the CM core out of reset and if so, can this be achieved by triggering an NMI on CPU1 from the CM core reset, which is then handled by calling Device_bootCM() within the NMI handler (Refer below code) or is there an alternative approach available?

// CPU1 Code

int main(void) {    
    SysCtl_enableNMIGlobalInterrupt();
    Interrupt_register(INT_NMI, nmiISR);
    SysCtl_enableCMtoCPUNMI(SYSCTL_CMTOCPU1INTCTL_CMNMIWDRST);
    Device_bootCM(BOOTMODE_BOOT_TO_FLASH_SECTOR0);
} 
__interrupt void nmiISR(void)
{
    if (SYSCTL_STATUS_CMNMIWDRST == SysCtl_getCMInterruptStatus()){
        Device_bootCM(BOOTMODE_BOOT_TO_FLASH_SECTOR0);
        SysCtl_clearCMInterruptStatus(SYSCTL_STATUS_CMNMIWDRST)
    }
    // Clear NMI flags
    intStatus = SysCtl_getNMIFlagStatus();
    SysCtl_clearNMIStatus(intStatus);
}

Could you please assist us in answering the above queries?

Thanks & Regards,

Vikram Tathe

over 1 year ago

0 Prarthan Bhatt over 1 year ago

TI__Mastermind 19296 points

Hi Vikram,

The CM WD is clocked by CMCLK

C28x WD is source from INTOSC1.

Yes when NMIWD timeout will trigger reset to CM, so C28 CPU1 needs to bring CM out of reset.

Vikram Tathe said:
units of the parameter passed to SysCtl_setNMIWatchdogPeriod

Its the counter value decremented every cycle at the WDCLK rate.

Thanks

0 Vikram Tathe over 1 year ago in reply to Prarthan Bhatt

Prodigy 175 points

Hello Prarthan Bhatt Vivek Singh Hareesh Janakiraman Baskaran Chidambaram Veena Kamath

I have LED1 blinky code running on CPU1 and LED2 blinky code on the CM core. I have implemented a watchdog feature on the CM core.

Intentionally, I am not handling the Non-Maskable Interrupt (NMI) on the CM core and not reloading the watchdog value, resulting in a reset of the CM core and the generation of an NMI on the CPU1 core.

Up to this point, I am able to debug the watchdog feature.

However, after the execution of the NMI on CPU1, the CM core won't come out of reset LED2 is not blinking. it seems due to the debug session being terminated due to the reset. How should I debug to find if the CM core comes out of reset or not?

CPU1 code is as below.

// CPU1 Code

int main(void) {  
    ...
    SysCtl_enableNMIGlobalInterrupt();
    Interrupt_register(INT_NMI, nmiISR);
    SysCtl_enableCMtoCPUNMI(SYSCTL_CMTOCPU1INTCTL_CMNMIWDRST);
    Device_bootCM(BOOTMODE_BOOT_TO_FLASH_SECTOR0);
    ...
} 
__interrupt void nmiISR(void)
{
    if (SYSCTL_STATUS_CMNMIWDRST == SysCtl_getCMInterruptStatus()){
        Device_bootCM(BOOTMODE_BOOT_TO_FLASH_SECTOR0);
        SysCtl_clearCMInterruptStatus(SYSCTL_STATUS_CMNMIWDRST)
    }
    // Clear NMI flags
    intStatus = SysCtl_getNMIFlagStatus();
    SysCtl_clearNMIStatus(intStatus);
}

Thanks & Regards,

Vikram Tathe