topic Re: UART inverter K27/28 in Kinetis Microcontrollers

UART inverter K27/28

javierhernande1 — Sat, 28 Apr 2018 00:24:44 GMT

Hello,

K27/28 has DTE/DCE interfaces like as iMX family?

or is there any other way to invert a UART connection without the need to add an external circuit?

Is not this a problem with FLEXIO?

I need to invert the UART connection to Futaba S.BUS and FrSky Smartport.

Best regards

Re: UART inverter K27/28

mjbcswitzerland — Sun, 29 Apr 2018 16:07:00 GMT

Hi Javier

The KL27/KL28 UARTs/LPUARTs don't have the ability to switch between DTE/DCE internally but if you can connect UART_TXx and UART_RXx (and others needed) together from 2 mux pins you can switch between the two (set the valid direction pin to its UART function and the other as GPIO input).

Regards

Mark

uTasker developer and supporter (+5'000 hours experience on +60 Kinetis derivatives in +80 product developments)
Kinetis: http://www.utasker.com/kinetis.html

Re: UART inverter K27/28

javierhernande1 — Sun, 29 Apr 2018 21:04:38 GMT

Hi Mark,

Thank you for the reply,

I have not understood it very well, so I am going to implement the external circuits for S.Bus and Smartport, just in case I can not do it via software.

With FlexIO is not easier.

By the way, uTasker supports FlexIO?

Normally when an inverter is not added, the inverted signal is used from the receiver. But you have to be modifying the receiver. As explained here.

Regards,

Javier

EDITED: I have done these circuits to S.Bus and Smartport

Re: UART inverter K27/28

mjbcswitzerland — Mon, 30 Apr 2018 12:46:52 GMT

Hi Javier

I do not yet have FlexIO integrated into the uTasker project but I expect to be adding FlexIO UARTs shortly.

It is however also possible to use NXP FlexIO code together with the project.

Regards

Mark