MPC5748G LINFlexD UART Baud Rate

[w0wy]

Hello all,

I am having some problems with sending data over UART from MPC5748G to my PC.

The thing is that I have a MPC5748G board which is receiving FlexRay frames via the FlexRay port and is sending these frames (with a custom layout) via the UART to the PC.

The receiving part is working correctly but the sending via UART does not work with other BaudRate than 9600.

I am using a simple python script with PySerial in order to receive the data (I've also checked with PuTTy).

What actually happens is that if I use higher BaudRate than 9600, the data gets received up to a point (sometimes is gibberish), but then, it just stops. I am not 100% sure that is the actual sending from the board or maybe there is something wrong with related to the PC(software or hw wise).

Can anybody help me ? The data continues to be sent from the board (checked in DEBUG mode).

Also, I've read somewhere in the reference manual that the max BaudRate that can be set is 48000 for the MPC5748G. Is this true ? Or I should be able to also use 115200 ? 

Thank you

[BenMW]

I'm currently using LINFlexD1 for UART with a baudrate of 921600 bps on a custom board. This works fine!

The possible baudrate is specified in reference manual part 45.4.4. UART mode, with a "baud rate of up to LIN_CLK/4 Mbit/s". So there is no such a limit as you expected for this chip.

I tried with up to 4 Mbit/s, but the USB/UART bridge on my board is not able to have a higher transfer rate than 921.6 kbit/s.

[lukaszadrapa]

Hi,

did you check the TX line by a scope or logic analyzer? That's the easiest option to check which side is causing the troubles.

You should be definitely able to use speed 115200 (and even more).

Regards,

Lukas

[w0wy]

Hello,

Thanks for the reply. Will probably get the chance to check using a scope somewhere around next week.

Still, this is very good info.

You should be definitely able to use speed 115200 (and even more).