Is it dead? FAIL.TXT

Derek Kwan · ‎2017-10-23

Posted on October 23, 2017 at 21:37

Excited getting the STM32L476 Nucleo-64 board from the ST event last week. Was trying to program it past few days. Tried some examples from mbed with IDW01M1 WiFi module. But it was iffy, at times program just hangs, hitting reset it will work for a while...

Then this afternoon, all of the sudden, board failed to respond. And the USB drive shows up with a FAIL.TXT contain the following message 'The interface firmware FAILED to reset/halt the target MCU'

OK, that explains what happens. Hitting reset button does nothing. Time to check with Google... Followed a few suggestions...

Tried STSW-LINK007 with 'ST-LinkUpgrade.exe', update seems to work. (but just mean ST-Link is working, not the STM32L476)

Tried to flash again following the example from ST workshop using 'CleanAzure_Sns_DM.bat', as expected, report No target connected (again because STM32L476 is dead?)

As someone suggest to use Windows STM32 ST-LINK utility', holding RESET button and do target -> erase chip, no go.

Question: Is it dead? If yes, too bad, my experience is short lived.

:(

#stm32l476-eval-board #fail.txt #stm32l476

Derek Kwan · ‎2017-10-23

Posted on October 23, 2017 at 23:31

Looking into the board and digging up schematics...

U4 (LD39050PU33R) is dead, output 0.3V vs 3.3V, and it was burning hot! Now according to

schematics. JP6 (IDD) jumper is for measure current use. *Ah-ha moment* I just need to remove the jumper (to separate the faulty U4) from 3.3V rail, then I apply external 3.3V....

Yes, it is sort of working, I was able to flash one of the blinker binary with ST-LINK and appear to work. ST-LINK was able to identify the MCU correct (although still gives FAIL.TXT). But doesn't always works, worked only once or twice...

So, all in all, I think I may have a bad board to begin with, as I was suspecting power issue all along, because during Tx (according to data sheet) , SPWF01SA could draw 100+mA. Yes, I know LD39050PU33R was design to supply 500mA, but...

Also, I think it may worth to mention, according to documentation, JP1 should be CLOSED to allow more than 100mA draw [when using WiFi module]...