UCD3138A: PMBUS UCD3138: No devices found No ROM detected

Martin

Part Number: UCD3138

Hello, I was recently learning the PMP23340_UCD demo board .

I met a serious problem about download code into the demo board.

I tried to clear the DataFlash during debugging and it finally showed that I was doing it wrong and PMBUS could not communicate with the chip.

I tried to solve this this problem and found this in the code.

This line of the function is commented out in the program

So I expect to know how can I solve these problems?

Looking forward to your reply, thank you very much!

21 days ago

0 Jonathan Wong 21 days ago

TI__Expert 3630 points

Hello A Yang,

That line of code is used to debug the firmware since it gives you an additional hardware reset. For production purposes it is not needed but for debug purposes you can use it. Please see the following E2E posts on the code's purpose:

Regards,

Jonathan Wong

0 Martin 16 days ago in reply to Jonathan Wong

Prodigy 110 points

Thank you,Jonathan.

I'm sorry, but the discussion mentioned in your reply doesn't address my question.In fact, I thought about it and looked for a solution.

But I noticed that this code in the main program is commented out .Then because of some mishandling, something went wrong.

The GUI now shows：No devices found No ROM detected.

How do I solve the problem in this situation? Can I only replace the chip?

	//Check to see if FAULT2 is pulled high and FAULT0 is pulled low.
	//If they are go to ROM.
	if (MiscAnalogRegs.GLBIOREAD.bit.FAULT2_IO_READ && !MiscAnalogRegs.GLBIOREAD.bit.FAULT3_IO_READ)
	{
//		pmbus_read_write_rom_mode(PMBUS_WRITE);
	}

Best Regards.

0 Ning Tan 15 days ago in reply to Martin

TI__Intellectual 1255 points

Yang,

Please give us few days to investigate the issue.

Thanks

0 Jonathan Wong 12 days ago in reply to Ning Tan

TI__Expert 3630 points

Hello Yang,

Based on your GUI, it looks like you cannot find the UCD in ROM mode or Flash mode. Does switching the power on/off help at all? If not, then your chip may be locked in Flash mode. If it is locked in Flash mode, then there is not much you can do besides use a new chip. It is useful to include the hardware backdoor code since that will ensure your chip will not be locked in Flash mode. The code was commented out so that the user can choose to include or not include the hardware backdoor. Try using a new UCD chip and uncomment the hardware backdoor code.

See this E2E post for more information: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1356278/ucd3138allcevm150-fault-pins-assignment-in-llc-evm-firmware

Regards,

Jonathan Wong

0 Martin 12 days ago in reply to Jonathan Wong

Prodigy 110 points

Hello Jonstan,

I've replaced the chip, but I'm more interested in finding the cause of the previous error.

If it is locked in Flash mode, why can't I find the UCD in Flash mode?

I got an error after doing this step.Is there a problem with the operation?

(The GUI may crash while doing this step, I'm not sure...)

Best Regards.

+1 Jonathan Wong 11 days ago in reply to Martin

TI__Expert 3630 points

Hi A Yang,

Please see the training lab video on the UCD locked flash problem: https://www.ti.com/video/series/introduction-to-digital-power-controllers.html. Specifically, "UCD3138 Digital Power Tools: Boot ROM and program flash checksums" at the 4:00 minute mark talks about the locked flash.

In summary, a potential bug in your code would keep your program stuck in a loop. If it is stuck in a loop, then it will never run the pmbus_handler(), which allows the UCD to communicate w/ the GUI, whether it is in ROM mode or Flash mode. Thus, your UCD will be stuck in Flash mode and there will be no way to get the UCD out of the loop. Having a hardware backdoor that forces the UCD to execute the pmbus_handler() routine or forces the UCD to go back to ROM mode will prevent your UCD from getting locked in flash mode.

I am not sure why you are using the Fusion Studio Design GUI. The UCD3xxx Device GUI is what you should be using to detect and flash the UCD firmware.

Regards,

Jonathan Wong

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UCD3138A: PMBUS UCD3138: No devices found No ROM detected