Trouble with setting the GPIO pin value

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Trouble with setting the GPIO pin value

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alam1
Contributor I

Hi

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

gpio-pins-33-116.pnggpio-33-116-status.png

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

gpio-status-pins.png

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

gpio-pins-problem.png

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

How can I make them low during boot up.

Thanks

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igorpadykov
NXP Employee
NXP Employee

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"

i.MX 6Solo/6DualLite Applications Processors for Consumer Products

 

Best regards
igor

 

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alam1
Contributor I

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.

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igorpadykov
NXP Employee
NXP Employee

>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

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1,990 Views
alam1
Contributor I

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

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igorpadykov
NXP Employee
NXP Employee

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

 

Best regards
igor

 

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