topic Re: GPIO HI-Impedance configuration and pullup/pulldown in MK20DX series ? in Kinetis Microcontrollers

GPIO HI-Impedance configuration and pullup/pulldown in MK20DX series ?

michelecanepa — Wed, 16 Jul 2014 10:34:24 GMT

Dear Sirs,

I have few questions:

Does anyone knows if there's the possibility to configure the GPIO pins on K20 Sub-family microcontrollers MK20DX64VLH7, MK20DX128VLH7, MK20DX256VLH7 to put them in HI-Z status?
The GPIO's do have a pullup or a pulldown? In what GPIO conditions?
Are there different strengths for the GPIOs current capability? Are the strengths configurable, or there are differences from pin to pin?
In reset condition, or start-up condition, what is the GPIO status, in term of direction, pullup configuration, output status?

I could not find that information on the documents I've read, that are:

K20P64M72SF1

Rev. 3, 11/2012

K20P64M72SF1RM

Rev. 1.1, Dec 2012

Do I need any other document?

Thank you everybody.

Best regards,

Michele Canepa, Electrical Engineer.

Re: GPIO HI-Impedance configuration and pullup/pulldown in MK20DX series ?

egoodii — Wed, 16 Jul 2014 12:29:06 GMT

Referencing:

K20P64M72SF1RM

Rev. 1.1, Dec 2012

1 - All GPIO are 'Hi-Z' when configured as inputs -- see 49.2.6.

2 - Most GPIO pins have the options under 'PORT control' 11.14.1, the pull-enable and up/down being the two LSBs.

3 - See above -- also a function of PORT control.

4 - All GPIO pins will be 'input' (Hi-Z) as per the 'reset condition' outlined in 49.2.6. However, for a complete definition of 'pin state at reset' refer to chapter 10. 10.2.2 lists some 'special' reset-values for some members of Port A PORT control, but more particularly the table in 10.3.1 lists the 'default' operational-mode for every pin on the package. Most pins default to their 'analog' function -- Alternate '0' -- (except the debug pins, on Port A, as selected by those 'special' PORT control values), as this has the least restriction on external connections.

Re: GPIO HI-Impedance configuration and pullup/pulldown in MK20DX series ?

michelecanepa — Wed, 16 Jul 2014 12:55:20 GMT

Thank you very much Earl !

The answers to all my questions are definitely in that document.

Best,

Michele

Re: GPIO HI-Impedance configuration and pullup/pulldown in MK20DX series ?

egoodii — Wed, 16 Jul 2014 13:03:26 GMT

I freely acknowledge that pulling a 'full picture' of functions from these 1000+ page documents can be daunting. In particular, these Freescale Kinetis manuals suffer from a confusion in that the 'peripheral function' descriptions are 'generic' per the design of that silicon module, but many times you have to correlate info from Chapter 3 (and other places!) to understand what clocks/options/shortcomings come with a particular 'chip'.

Additionally, they DON'T document any details that are considered 'ARM core', leaving THAT to be culled from www.arm.com.