topic Re: GPIO reset state? in Kinetis Microcontrollers

GPIO reset state?

idtericchen — Mon, 01 Dec 2014 09:12:15 GMT

I want to know the K21 GPIO state during reset.

Where can I find these information?

Could I change the GPIO reset state? If it can be changed, how to do?

Re: GPIO reset state?

Jorge_Gonzalez — Mon, 01 Dec 2014 16:50:07 GMT

Hello Eric Chen:

- For digital-only pins the default state is as DISABLED (high impedance).

- For pins with an analog functionality, those acquire their analog function.

You can refer to the chapter "K21 Signal Multiplexing and Pin Assignments" in the Reference Manual to see which pins are digital, analog or digital + analog.

If you mean the value of the GPIO registers out of reset, then that information is in each register description, again in the reference manual. e.g. for the GPIOx_PDOR register:

None of the above behaviors can be changed.

In case you cannot find the reference manual in our webpage, please let me know the full part number of your K21 device.

Regards!,
Jorge Gonzalez

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

Re: GPIO reset state?

idtericchen — Tue, 02 Dec 2014 01:22:20 GMT

Hello Jorge:

Thanks for your quickly response.

You mean the digital-only pins the default state is as DISABLED (high impedance) during reset.

So if I want to control GPIO state is HIGH during reset, I need to add external pull-up resistor on this GPIO, right?

For example, If I want the PTD8 to output HIGH during reset, I need to add external pull-up resistor on PTD8, right?

Re: GPIO reset state?

Jorge_Gonzalez — Tue, 02 Dec 2014 02:06:19 GMT

Hi Eric:

You are correct, for a high state in PTD8 during reset you can place a pull-up resistor.

Regards!

Jorge Gonzalez

Re: GPIO reset state?

王剑翰 — Fri, 30 Jan 2015 03:55:56 GMT

Hi Jorge,

- For digital-only pins the default state is as DISABLED (high impedance).

- For pins with an analog functionality, those acquire their analog function.

Is the above information for all Kinetis unit? I used MK10DN32VFM5.

Look forward to your kindly answer.

Re: GPIO reset state?

Jorge_Gonzalez — Fri, 30 Jan 2015 16:57:37 GMT

Hello:

Yes the same applies for your K10 device and any Kinetis K part.

Regards!

Jorge Gonzalez