MSP430FR5739: Problem with JTAG unlock after wake up

Nikolai Kalchev

Part Number: MSP430FR5739
Other Parts Discussed in Thread: MSP-EXP430FR5739

Hello guys,

I have a strange problem... I`m using MSP430FR5739 in my design. So far I have successfully lock and unlock JTAG in normal mode but when the device enter LPM4, I cannot connect with the debugger anymore. MSP wakes up with a low level on a pin. The whole procedure is working (go to sleep - wake up) properly. Why I cannot unlock the device? Do you have any idea what is the problem. I`m using MSP-EXP430FR5739 Experimenter Board. Thanks in advance!

Best Regards

over 7 years ago

0 zrno soli over 7 years ago

Guru 34283 points

Maybe it is related to supply voltage. JTAG / SBW can not work with FRAM devices on 1.8V.

0 Nikolai Kalchev over 7 years ago in reply to zrno soli

Prodigy 50 points

The supply voltage is 3.3V. The problem is somewhere else....One thing to mention, on the original board it is working, but on my pcb it is not. What can be the problem..I follow the reference design....

0 zrno soli over 7 years ago in reply to Nikolai Kalchev

Guru 34283 points

cap on vcore pin is present?

0 Nikolai Kalchev over 7 years ago in reply to zrno soli

Prodigy 50 points

Yes, 100nF.

0 zrno soli over 7 years ago in reply to Nikolai Kalchev

Guru 34283 points

Nikolai Kalchev said:
I follow the reference design....

Nikolai Kalchev said:
Yes, 100nF.

On EXP board it is 470nF. Try to find what else is different between your and EXP board.

0 Nikolai Kalchev over 7 years ago in reply to zrno soli

Prodigy 50 points

Just tried with 470nF, it is the same. I check every other element in reference design. There is no difference. I`m running out of ideas....

0 Nikolai Kalchev over 7 years ago in reply to Nikolai Kalchev

Prodigy 50 points

Hello again. I tried with LPM3 mode. It is working properly, I can unlock JTAG with the correct password. The question is why it is not working with LPM4. I want lowest power consumption, because our application is battery powered. We have bough over 5k chips so I hope it is not an undocumented bug...

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MSP430FR5739: Problem with JTAG unlock after wake up