Reset From 16U2 To 328P

[Ignasi Soler]

Hi Robert,

In the 28Pins project we can reset the 328P from the 16U2, through a series capacitor. I think we should add a reverse biased diode after the capacitor to avoid a positive glitch (of 2xVCC) when the reset signal from the 16U2 processor rises, isn't it?

In the pictures, the voltage VA is what will see the AND gate if there's no diode, with a glitch that doubles the supply voltage. If we add a diode, the voltage remains within the limits (VB).

Regards

Ignasi

[robertferanec]

Good question. I believe there should be protection diodes inside the chips. I think I did measure it when I was designing the circuit, but I do not remember exactly. Did you try measure it (I mean the real board)?

[Ignasi Soler]

No, I haven't done yet. I'll try to play this weekend with the Arduino board and measure the signals. I'll let you know
Thanks

[robertferanec]

Thank you.