topic Re: k66 RESET_b is pulled down by chip in Kinetis Microcontrollers

k66 RESET_b is pulled down by chip

1043064987 — Tue, 07 Jul 2020 04:30:37 GMT

I use Jlink commander "unlock kinetis" but it time out.

There's only one 4.7k pull up resistor on RESET_b but it always at 30mV.

myke_predko — Tue, 07 Jul 2020 06:07:08 GMT

Hiya,

How are you connecting the other JTAG pins?

A couple of notes:

I put a 4.7k pull up on JTAG_TMS
Also, make sure that EZ_C_b is left open (we've been discussing that here: EZ_Port Pin Standard Config Pull Up Down

myke

1043064987 — Tue, 07 Jul 2020 06:32:33 GMT

Hi Myke,

Thanks for your notes. But when TMS is open, TMS is 3.3V. And after EZ_CS_b is left open, the RESET_b changes to 0.2V.(no longer 30mV)

myke_predko — Tue, 07 Jul 2020 14:57:08 GMT

Hiya,

Can\ you put in a drawing of your programming circuit and the different signal levels?

Attached is the circuit I use for programming to the Segger JLink Plus (should be the same connections as you use) and the Segger Needle connector:

Just a couple of notes:

myke

1043064987 — Wed, 08 Jul 2020 04:50:13 GMT

Hi,

Thank you. Finally, I solder a new one and it's all right. Maybe when I soldered the last one, temperature was so high and burn the chip.

myke_predko — Wed, 08 Jul 2020 14:30:00 GMT

Good news - keep us updated as to your ptogress!