reset pin generates a square wave

[mehmetekici]

Hello,

We have come accross a problem with our design. Some of our boards has very strange behaviour on their reset pin. We see a squareware at reset pin.

We have one board with a brand new cpu and two others we had programmed with adc example provided by freescale.

Information on the  cpu package.

MK60DN512VLQ10  runs with 50 Mhz oscillator.

4N22D

OCTAA1250AA

you can see the details enclosed schematics also scoped reset

signal together with VDD. another measurement is taken after  reset circuit connection cut from the reset pin.

Best regards,

Mehmet

[Hui_Ma]

"If flash is not programmed, the reset vector is 0xFFFFFFFF , it is a illegal address, will cause reset.  In reset sequence, reset pin will drive out it is better to have pull up resistors with the reset pin."

So the waveform you observed is an expected behavior.