TMS320F28020: Recomended GPIO input capacitance

Part Number: TMS320F28020

May I have question about F28020 DS?

My customer is would like to install a capacitor in the GPIO pin, Since the GPIO input will malfunction due to external noise.

Question 1

Datasheet 8.6 -Input capacitance is for all GPIOs?

and is there min and max value?

Question 2

I think GPIO input is CMOS, so if install too big capacitance, it make mcu malfunction.

Is there any recomanded value of capacitor for install GPIO pins?

Thanks,

6 months ago

+1 Kevin Allen18 6 months ago

TI__Mastermind 40755 points

Hi GR,

GR said:
Datasheet 8.6 -Input capacitance is for all GPIOs?

The spec you're referencing is the typical amount of capacitance the pin / GPIO introduce, it is not how much external capacitance the pin can tolerate.

GR said:
Question 2

I think GPIO input is CMOS, so if install too big capacitance, it make mcu malfunction.

Is there any recomanded value of capacitor for install GPIO pins?

Yes CMOS. It'll depend on your GPIO switching and rise / fall time requirements. Note there is a +/- 4mA current spec for GPIOs. Sharing a similar E2E discussion below:

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/985362/tms320f28375s-gpio-pin-inrush-current-handling-capability

Best,

Kevin

0 GR 6 months ago in reply to Kevin Allen18

Expert 2676 points

Hi Kevin,

Thanks for your information.

I understand it.

If the capacity is calculated together with the switching frequency and the inrush current is less than 20 mA, it is OK.

Best regards,

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28020: Recomended GPIO input capacitance