i.MX ProcessorsのトピックRe: imx8mini set input high impedance

imx8mini set input high impedance

bobwang — Wed, 12 Aug 2020 02:25:34 GMT

How could I set IMX8MINI GPIO Pin input to high impedance (or float?) when I set no pull-up and pull-down, I measure voltage is 2.5V(with external resistor connect to 3V3), does that means internal still pull down?

This is want I got, I am not sure I set correct or not? if set correct what value could I get?

Re: imx8mini set input high impedance

Yuri — Wed, 12 Aug 2020 08:18:43 GMT

bobwang

Hello,

use the following settings of corresponding Pad Control Register:

PE (Pull Resistors Enable) = 0 (disabled);

ODE (Open Drain Enable) = 1 (enabled).

Regards,

Yuri.

Re: imx8mini set input high impedance

bobwang — Wed, 12 Aug 2020 23:48:49 GMT

Thank you very much, I'll try.

Re: imx8mini set input high impedance

bobwang — Mon, 17 Aug 2020 23:44:13 GMT

From NXP Errata ( MIMX8MM6DVTLZAA)for 3.3V IO operation using external resistors for pullup/pull down and disable the internal pull up/down via software.

I already set PE (Pull Resistors Enable) = 0 (disabled); ODE (Open Drain Enable) = 1 (enabled), and I found register value is 0x00000036.

I measured my GPIO input pin with an external resistor(pull up to 3.3V with 10k resistor) found it the vale still 2.5V.

I am confused, does that mean IMX8MINI not support 3.3V external or I am setting wrong. it likes like still internal pulldown.

Re: imx8mini set input high impedance

Yuri — Tue, 18 Aug 2020 05:21:37 GMT

bobwang

Hello,

Is the pin really free - there is no externally connected parts on the board?

Regards,

Yuri.