topic Re: Question, i.MX25 KPP port usage in i.MX Processors

Question, i.MX25 KPP port usage

Aemj — Tue, 05 Jan 2016 11:15:10 GMT

Hi team,

I would like to ask about KPP port of i.MX25.

My customer plans to use KPP_ROW6(V5 pin) port of i.MX257 as a GPIO output.

The customer believes that the KPP_ROW6 pin can be used to output High or Low at any desired timing.

Is it true?

Please let me know if you have any concern on that.

Thanks,

Miyamoto

Re: Question, i.MX25 KPP port usage

fabio_estevam — Tue, 05 Jan 2016 13:14:18 GMT

There is no GPIO functionality associated with this particular pin.

Regards,

Fabio Estevam

Re: Question, i.MX25 KPP port usage

Aemj — Wed, 06 Jan 2016 01:40:17 GMT

Hi Fabio,

Thanks for your reply but I need more detailed explanation on that.

I think the port, KPP_ROW6, can be configured as an output port by configuring Keypad Data Direction Register (KDDR).

And I think one can control the output level of KPP_ROW6 by writing 1 or 0 bit into KPDR[6].

Am I wrong?

Thanks,

Miyamoto

Re: Question, i.MX25 KPP port usage

Yuri — Wed, 06 Jan 2016 07:44:57 GMT

Hello,

KPP_ROW6 (V5) pin has no GPIO functionality as Fabio mentioned.

Nevertheless, You are right, the KPP in itself allows to control pin state.

KPCR[KRE6] = 0 (Row is not included in the keypad key press detect)

KDDR[KRDD6] = 1 (ROW pin configured as an output)

KPDR[KRD6] = 1/0 (data)

Have a great day,
Yuri

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Re: Question, i.MX25 KPP port usage

Aemj — Wed, 06 Jan 2016 09:09:43 GMT

Hi team,

The reference manual of i.MX25 says as below.

"The kKeypad port (KPP) is a 16-bit peripheral that can be used as a keypad matrix interface or as general

purpose input/output (I/O)."

Could you give your detailed reason why you say that KPP_ROW6 (V5) pin has no GPIO functionality?

Thanks,

Miyamoto

Re: Question, i.MX25 KPP port usage

fabio_estevam — Wed, 06 Jan 2016 10:02:18 GMT

Now I see the response from Yuri and understood that it is possible to program the KPP interface to use the pin as an output.

Sorry for the confusion.

Regards,

Fabio Estevam

Re: Question, i.MX25 KPP port usage

Yuri — Thu, 14 Jan 2016 04:35:39 GMT

Hello,

> why you say that KPP_ROW6 (V5) pin has no GPIO functionality?

Most of KPP signals can be configured as GPIO via IOMUXC_SW_MUX_CTL_PAD_KPP-...

registers, but the KPP_ROW6 does not have corresponding register.

Only the following ones are available :

IOMUXC_SW_MUX_CTL_PAD_KPP_ROW0

IOMUXC_SW_MUX_CTL_PAD_KPP_ROW1

IOMUXC_SW_MUX_CTL_PAD_KPP_ROW2

IOMUXC_SW_MUX_CTL_PAD_KPP_ROW3

IOMUXC_SW_MUX_CTL_PAD_KPP_COL0

IOMUXC_SW_MUX_CTL_PAD_KPP_COL1

IOMUXC_SW_MUX_CTL_PAD_KPP_COL2

IOMUXC_SW_MUX_CTL_PAD_KPP_COL3

Regards,

Yuri.