deskthority

Posted: **04 Jul 2015, 17:27**

Hello everyone, I just designed a 35% keyboard PCB which uses Teensy 2.0 as the controller.
And I just realized there are no resistors used in the keyboards to limit the current flow between input and output pins.

Is this because the controller input has high impedance?

Posted: **04 Jul 2015, 17:58**

b1gtuna wrote: ↑Is this because the controller input has high impedance?

Exactly

Posted: **04 Jul 2015, 18:08**

Ray wrote: ↑
b1gtuna wrote: ↑Is this because the controller input has high impedance?
Exactly

gracias!

Posted: **04 Jul 2015, 19:11**

To have some numbers: atmega internal pull-ups should be about 50k.

Posted: **05 Jul 2015, 17:59**

flabbergast wrote: ↑To have some numbers: atmega internal pull-ups should be about 50k.

Yup and I also checked that the maximum input/output current is 40mA. Thanks!

deskthority

No resistors are used to limit the current in keyboards?

No resistors are used to limit the current in keyboards?