i.MX6SDL GPIOx_PSR register value.

[satoshishimoda]

Hi community,

Our partner have a question about i.MX6SDL GPIO.

Please see chapter 29.5.2 in IMX6SDLRM Rev.1.

It says "If GDIR[n] is cleared and IOMUXC input mode is not GPIO, then reading DR[n] always returns zero".

With same condition (GDIR[n] is cleared and IOMUXC input mode is not GPIO), how about the value of GPIOx_PSR register?

Does is return zero same as GPIOxDR register?

Best Regards,

Satoshi Shimoda

[Yuri]

   GPIOx_PSR register(s) is intended to read actual state of internal

signals, as it is configured by IOMUXC.  Please look at  Figure 29-1

(Chip IOMUX Scheme) of the IMX6SDLRM.

Have a great day,
Yuri

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[satoshishimoda]

Hi Yuri,

Thank you for your reply.

> as it is configured by IOMUXC. 

Sorry, I did not understand well the meaning of the above your comment.

Which is correct?

A. GPIOx_PSR can get actual pad state even if IOMUX is not set to GPIO.

B. GPIOx_PSR can get actual pad state only when IOMUX is set to GPIO.

Best Regards,

Satoshi Shimoda

[Yuri · Accepted solution]

The PSR register reflects state of pin in (GPIO) input mode.

(case B)

~Yuri.

[satoshishimoda]

According to your reply, GPIOx_PSR does not return the actual pad state when IOMUX is not set to GPIO.

Then, what value is returned when read GPIOx_PSR in the case?

Zero? Indeterminate value? or keep actual pad state if the out of reset condition is "GPIOx_IOxx/Input/PU(100K)" of the pad?

Best Regards,

Satoshi Shimoda

[Yuri]

"The IOMUX must be configured to GPIO mode for PSR to reflect the state
of the corresponding signal. Otherwise the register shows the default values

as set by the IOMUX."

~Yuri.