IMX8M mini evk expansion connector

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IMX8M mini evk expansion connector

473 Views
Chayma
Contributor III

Hello everyone,

I am developing a functionality under the imx8m mini evk.
I want  to use one of the expansion connector pin as an interrupt pin for my driver.
I chose the EXP_IO10 but it seems it's connected to an I2C IO expansion. 
Could anyone help and find a way to work with that pin or is there any other pin that can be used directly without interacting with I2C.

Thank you in advance.

 

Best regards,

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6 Replies

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Chayma
Contributor III

@weidong_sun 

here the external pull-up schematic
MicrosoftTeams-image (5).png

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321 Views
Chayma
Contributor III

Dear @weidong_sun 
I am sorry for the late reply I had been working on other work. Now I get back to this problem
I have tried the external pull-up way. How can I disable the internal pull up for the pin?
Thank you.

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464 Views
weidong_sun
NXP TechSupport
NXP TechSupport

Hi,

See pins in blue rectangle, they all can be used as GPIO.

weidong_sun_0-1632908150023.png

You only need to multiplex one of them in dts. 

For example, if you want to use SAI5 pins, such as SAI5_RXD0, you should comment node below in imx8mm-evk.dtsi.

/*

&micfil {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_pdm>;
assigned-clocks = <&clk IMX8MM_CLK_PDM>;
assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
assigned-clock-rates = <196608000>;
status = "okay";
};

*/

By default, these pins are used for PDM.

Then add SAI5_RXD0 to iomux node to be a GPIO .

IOMUX definitions are in imx8mm-pinfunc.h .

 

Have a good day!

Regards,

weidong

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452 Views
Chayma
Contributor III

@weidong_sun 

Hello,

 

Thank you for your support.

Adding the pin to the pinctrl node requires the pin ID.
The code below is the pinctrl I defined in my device tree : 

pinctrl_intrpt: intrptiogrp {
fsl,pins = <
MX8MM_IOMUXC_SAI5_RXD3_GPIO3_IO24 0x00000005
>;
};

(Is the Pin ID correct ?)

and then I add it in my driver node :

pinctrl-0 = <&pinctrl_intrpt>;
interrupt-parent = <&gpio3>; // Data ready interrupt pin
interrupts = <24 IRQ_TYPE_EDGE_FALLING>;// gpio3.IO[24] Falling Edge

Please correct me if there is something wrong.

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444 Views
Chayma
Contributor III

@weidong_sun 

Hello,

The interrupt pin that will be used should be set as pull up (Hardware).

Is there a pull up pin in J1003 connector.

Thank you.

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439 Views
weidong_sun
NXP TechSupport
NXP TechSupport

Hi,

Very sorry!
We have a 7-day holiday for China’s National Day, and we just returned to the office today!

please try the setting for the GPIO pin:

0x41

>>Is there a pull up pin in J1003 connector.

If you want to use 3.3V IO, external pull up should be needed. and disable internal pull up/down

[Note]

For 3.3V IO, warning is maked in it's schematic.

If 1.8V IO, you can use internal pull up.

 

Try it please!

Have a good day!

Regards,

weidong

 

 

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