topic Re: UART problem on K60 (parity) in Kinetis Microcontrollers

UART problem on K60 (parity)

UniversalTroope — Fri, 10 Jun 2011 14:13:24 GMT

Hello, I'm having some problems with UART3 on the K60 Tower board (Rev. C) (the one that's connected to the RS232 port on the serial board).

I'm trying to send data out, but when I want to use parity, I get only garbage (verified on two computers, with two different serial cables).

The included source file replaces nill.c in the MQX 3.7 example nill.

I'll be very happy if someone can see where the problem is, or even just verify the problem on their K60/serial board.

Re: UART problem on K60 (parity)

UniversalTroope — Mon, 04 Jul 2011 17:05:54 GMT

Exactly the same problem on UART 1.

Has anyone successfully used parity on any Kinetis UART?

Re: UART problem on K60 (parity)

anthony_huereca — Wed, 06 Jul 2011 02:30:21 GMT

Make sure the terminal settings are set up correctly. In 8-bit mode, the 8th bit is the parity bit, and thus you only have 7 data bits. So make sure the terminal is setup for only 7-data bits.

If you need 8-data bits, then the UART should be setup in 9-bit mode.

See the note in Section 51.3.8 or section 51.4.4.1in the RM.

-amh

Re: UART problem on K60 (parity)

mjbcswitzerland — Wed, 06 Jul 2011 19:40:25 GMT

Regards

Mark

Re: UART problem on K60 (parity)

UniversalTroope — Thu, 07 Jul 2011 16:56:51 GMT

Thanks! Setting options to 9 databits solved the problem.

I'm using the MQX driver, and not bare metal. It seems like something the MQX driver should take care of, or at least should be mentioned in the serial driver section of the MQX I/O drivers user guide. Maybe it's a standard way to do it, and I just have insufficient serial port driver experience, but it's not exactly logical.

Re: UART problem on K60 (parity)

anthony_huereca — Thu, 07 Jul 2011 21:22:12 GMT

How each part implements parity can be different. So while on Kinetis it means you only have 7 data bits, on a S08 part it still might mean you have 8. So it does requires a little bit of knowledge of the part in this case, since the driver is just turning on parity for your part, and doesn't know neccesarily what you "meant" to happen. Someone else moving from bare-metal to MQX might think it odd if it didn't take away a data bit for example

-amh