topic Trouble with setting the GPIO pin value in i.MX Processors

Trouble with setting the GPIO pin value

alam1 — Thu, 03 Sep 2020 06:58:36 GMT

I am new to embedded system.

I am using i.mx6dl on a custom board running ubuntu 16.04.

Linux kernel: 4.1.15

I have to integrate murata wifi module using sdio interface for which the gpio pin number 33 and 116 has to be low during bootup.

I have tried the make them low in the following manner

I checked the status of gpios. I can see 33 and 116 are set to low

But after rebooting it and again I checked the status. Those pins are not present.

I checked those pins using multimeter, they are still high.

How can I make them low during boot up.

Thanks

igorpadykov — Thu, 03 Sep 2020 10:36:20 GMT

Hi alam1

pins state is not retained after rebooting, it is set to values described in

Table 97. 21 x 21 mm Functional Contact Assignments, column "Out of Reset Condition"

Best regards
igor

alam1 — Fri, 04 Sep 2020 06:47:16 GMT

Hi igor

I checked the table which you have mentioned.

The pins are set to high.

How can I make them low?

I tried to make low from uboot, still the problem is not solved.

igorpadykov — Fri, 04 Sep 2020 07:24:04 GMT

>How can I make them low?

there is no way to change it after reset, as it is defined in hardware.

One can set necessary value for example in uboot/

Best regards
igor

alam1 — Fri, 04 Sep 2020 07:35:47 GMT

I made them low from uboot.

But the issue is its still high after reboot.

I checked it with multimeter.

I want to the pins to low during bootup and then get high.

Is this possible??

Thanks

igorpadykov — Sat, 05 Sep 2020 06:15:06 GMT

no this is not possible as it is defined in hardware.

Best regards
igor