TMS320F280039C: LAUNCHXL-F280039C SCI Baud Rate Accuracy Issue

allen yang

Prodigy 100 points

Part Number: TMS320F280039C
Other Parts Discussed in Thread: LAUNCHXL-F280039C, SYSCONFIG, C2000WARE

Tool/software:

Hi TI Experts,

I am using the LAUNCHXL-F280039C for SCI communication. My baudrate is set to 500k,

but the measured signal baudrate is around 470k.

This results in an approximate 6% error, which causes data parsing errors when communicating with other devices.

Could you please advise on how to correct this issue?

1 month ago

0 allen yang 1 month ago

Prodigy 100 points

Hi
SDK information is as follows:

BR,

Allen

0 Peter Luong1 1 month ago in reply to allen yang

TI__Genius 14011 points

Hi Allen,

What value do you have selected for the LSPCLK in your SYSCTL registers?

Regards,

Peter

0 allen yang 1 month ago in reply to Peter Luong1

Prodigy 100 points

Hi Peter,
My LSPCLK is configured as shown in the diagram below.

The MCU's main frequency is 120 MHz, and the LSPCLK is divided by 4, resulting in 30 MHz

Best regards,
Allen

0 allen yang 1 month ago in reply to allen yang

Prodigy 100 points

Hi Peter，
I set the LSPCLK to 12 MHz, and now the UART baud rate is working fine.

Thanks，
Allen

0 Peter Luong1 1 month ago in reply to allen yang

TI__Genius 14011 points

Hi Allen,

The Baud rate calculation has some inherent error depending on the LSPCLK value you configure to the microcontroller. In SysConfig, there is a calculator which will tell you what the actual baud rate is and the error from the expected baud rate

Regards,

Peter

0 Peter Luong1 1 month ago in reply to Peter Luong1

TI__Genius 14011 points

This feature is on the latest version of the SysConfig tool so you may need to update C2000Ware. Or you can use the online version of SysConfig to see the calculations

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C2000 microcontrollers forum

TMS320F280039C: LAUNCHXL-F280039C SCI Baud Rate Accuracy Issue