MQX Software SolutionsのトピックRe: SCI High speed

SCI High speed

oscar — Fri, 02 Sep 2011 14:04:21 GMT

I'm trying to communicate at serial high speed (460800 bps and 921600 bps) but I received wrong characters.

My design:

- I'm using the serial MQX driver (3.7) in interrupt mode and I configured it for this speed (other speeds works well).

- I'm using a 48MHz crystal.

I read that it's possible to use (the baudrate register supports it).

Any idea about this topic?

Thanks in advance.

Re: SCI High speed

GottiLuca — Fri, 02 Sep 2011 14:31:41 GMT

Dear Oscar,

I have had same issues with MQX 3.7 with TWRK60 BSP . Follow this link for the details and a possible solution :

https://community.freescale.com/thread/87446

Re: SCI High speed

oscar — Fri, 02 Sep 2011 14:48:20 GMT

First, thanks for your quick response.

I saw your suggestion but I'm using the MCF52259 and it doesn't has a Baud Rate Fine Adjust (BRFA) register or similar....

Re: SCI High speed

DavidS — Fri, 02 Sep 2011 20:24:21 GMT

Hi Oscar,

It's been awhile since I ran a test to see how fast the UART can run on ColdFire but what I recall is that the raw UART signal was fine but the UART transceiver has a lower max frequency capability. I think I used oscope on input and output of transceiver to see the signal integrity to determine what was the system max frequency/baud I could use.

Hope this helps.

Regards,

David

Re: SCI High speed

oscar — Tue, 06 Sep 2011 19:04:35 GMT

It's a communication between 2 microcontrollers ( no transceivers used) . The problem is: High %error transmission when when using the internal clock source...I'm thinking to use a external clock source...