TMS320F28027: MCU reset unexpected

Strong ZHANG

Part Number: TMS320F28027

Hi Team,

My customer want to take a check what would happen if they enable interrupt but did not initialize the PIE vector table, they uncomment the function below, but enable the PWM interrupt, and disable watchdog, when they run the code which boot from FLASH, then will generate CPU reset, question is why would generate CPU reset as already disable watchdog and the input voltage is stable at 3.3V? it should have run to some unknown area and would not generate CPU reset.

it can reproduce this issue by using the example code attached, and set a breakpoint at the code before while function. or run the code without connected to ccs and monitor the reset pin's waveform.

// InitPieVectTable();

//PieVectTable.EPWM1_INT = &epwm1_timer_isr;

PieCtrlRegs.PIECTRL.bit.ENPIE = 1;

PieCtrlRegs.PIEIER3.bit.INTx1 = PWM1_INT_ENABLE;

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/171/Example_5F00_2802xEPwmTimerInt.7z

// InitPieVectTable();

over 5 years ago

0 Vasudha Bhadoria over 5 years ago

TI__Genius 10845 points

Hi,

The above mentioned operation should not be done in any application. Does the customer have any use-case for this scenario? Are they trying to poll the interrupt flag? The flag at the peripheral level can be polled even without enabling the interrupt at PIE and CPU level.

Thanks

Vasudha

0 Strong ZHANG over 5 years ago in reply to Vasudha Bhadoria

TI__Expert 4420 points

Vasudha,

yes I agree there should not be any use-case for this scenario, actually customer face an issue in their product, and they are evaluating if there any potential risk in the software, they just want us to explain why in that condition the MCU will be reset rather than the code jump to some unknown area without reset?

0 Vasudha Bhadoria over 5 years ago in reply to Strong ZHANG

TI__Genius 10845 points

Hi,

Can you add the boot rom symbols and check which code is getting executed? Also check the reset cause in CpusysRegs.RESC register.

Thanks

Vasudha

0 Strong ZHANG over 5 years ago in reply to Vasudha Bhadoria

TI__Expert 4420 points

Hi Vasudha,

After reset, the code will always jump to main function, and I did not find the reset cause register CpusysRegs.RESC.

0 Vasudha Bhadoria over 5 years ago in reply to Strong ZHANG

TI__Genius 10845 points

Hi,

Were you able to resolve this issue? If not, we can discuss this over mail.

I tried the mentioned scenario in F2837x and the device reset is seen in my code as well. The code jumps to boot code.

Did you try loading the boot symbols and checked where exactly the execution stops?

Thanks

Vasudha

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TMS320F28027: MCU reset unexpected