Why do FRDM-KL26Z boards die ???

[mjbcswitzerland]

Hi All

Some time ago I had a FRDM-KL26Z and wanted to measure the processor's current consumption. Therefore I removed R2 and R3 (shunts) and added a jumper J5. Then I loaded code and measured the current in the J5 path. I then wanted to repeated and found that the OpenSDA no longer worked - USB not detected and the LED next to the chip was off.

Since the board was no longer usable I ordered a new one and when it arrived I could program it.

Some time later I wanted to measure the current again so did the same modification on the new board and things were OK - I could do the tests. A little later I applied power to the board via OpenSDA connector (without the J5 jumer in place) and the board died again....OpenSDA not recognised (its D+ line stays at '0') and the light next to it stays off.

So now I have killed two boards just be powering without the processor voltage being switched to the KL26 chip. The KL26 still runs (the program that was loaded previously is operating) but the OpenSDA chip is sort of dead (it has supply voltage, its VREG output is at 3.6V and its reset line is at '1').

I have around 30 FRDM boards in the lab, most modified to measure current and never otherwise had issues. But the FRDM-KL26Z has almost immediately died each time this is done. Why should removing the KL26 power cause the debugger to (seemingly consistently) die?

Regards

Mark

[kerryzhou]

Hi Mark Butcher,

   I used the FRDM-KL26 to do the power consumption frequently, I didn't meet the FRDM-KL26Z die problem before.

   After you removed the resistor R3 and R2,  you need to short the J5 to make the opensda combine KL26 work.

  Now, you said your board is die, after you short the J5, enter bootloader mode, can you see the device named as : BOOTLOADER?

 You can try to downloader the opensda or JLINK debugger firmware again.

  Please try it again on your side.

If you still can't make it work, please tell me the detail result.

Have a great day,
Kerry

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[mjbcswitzerland]

Thank your Kerry

That was a good idea and I could recover the board and in the process I now know what the problem is:

1. If J5 is removed the OpenSDA always starts in BOOTLOADER mode; J5 needs to be connected for it to start normally.
2. If I have the BOOTLOADER connected to my Windows 10 PC immediately the PC kills the OpenSDA program that was loaded since it's USB-MSD loading operation is not compatible with Windows 10 (known issue)
3. I have to reprogram the OpenSDA loader with a different Windows 7 PC

4. If I later work with the board and forget to connect J5 when attaching the OpenSDA USB connector, the OpenSDA debugger again gets destroyed and I have to repeat the process again.

The first board that failed can't be recovered - it looks like its complete power supply has failed. This is no problem as long as the second one can be kept alive....

Regards

Mark

[kerryzhou]

Hi Mark Butcher,

  About the win10 problem,  as I know, JLINK can support the win10. So you can program the JLINK fimware in the WIN7 system, then use it in the win10.

Wish it  helps you!

Have a great day,
Kerry

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