FRDM-KL25Z doesn't work anymore due to my poor soldering skill

[kai_liu]

A week ago, I decided to put 5x2 header on FRDM to use it as a general debugger for my custom KL25Z board. To be honest, I am a software engineer, who is not good at SMD manual soldering.

After soldering I found there are short-circuit among them by Multimeter. So I have to remove the header again.

But after doing all of these messy things, I found my FRDM doesn't work anymore.

Sometimes it blinks.

The OS always prompts it can not communicate with target MCU. Finally I found the RST pin from OpenSDA K20 to target KL25Z is almost zero (about 0.7V). I pull up the RST with a jumper. The user application runs well. But since the RST pin can not controlled by OpenSDA, its complains all the time. Furthermore, since I am using jumper to enforce pulling up, so the voltage is not stable, which can be checked by the brightness of LEDs.

I checked the circuit, I found the SWD debugger interface are all protected by buffer IC, with only exception: RST pin.

Is RST pin of K20 skewed up? Any ideas? Otherwise I have to throw it away and buy a new FRDM. Still I am afraid of soldering the SMD header. Why not populating SMD out of fab?

[kai_liu]

I have ordered two boards from a trader. One for FRDM-KL25Z, the other is FRDM-KL05Z just in case I skewed up another KL25Z.

Yes, my consideration is right. I almost brick KL25Z this afternoon. I found the PIN3/5 (GND)are not heat isolated, it makes things worse. More heat, more tries, more short circuit.

And KL05Z board has much better design. And it takes me less than one minute to manually solder it on board.

Anyway, after these mess. They are all working now.

There is another amazing thing, the old one came back to life. I don't know why. But one thing I know I can not use it as external debugger anyway since I have done too much on its 5x2 sockets.

I hope the later release of FRDM can populate all through hole components as default options, including all user SWD/JTAG sockets, headers, jumpers.