TMS570LS0432: SPI to emulate UART transmit

Vikram Jain

Part Number: TMS570LS0432

Hi All,

The above device has only 1 UART port and i want to have another UART port for debug transmission is it possible that we can use a SPI (SPI3) port and configure it to work as UART for 115200 baud rate ? Is it actuall possible to use SPI for UART comms ?

Thanks in advance for your help.

over 7 years ago

0 Bob Crosby over 7 years ago

TI__Guru 72500 points

It is possible, if you only want to transmit. Use 10 bit data transmission and include a start bit (0) and a stop bit (1) around your 8 bits of data. Another option is using the N2HET to emulate a UART. See the links at the end of this thread:
e2e.ti.com/.../229245

0 Vikram Jain over 7 years ago in reply to Bob Crosby

Intellectual 485 points

Hi Thanks for your reply but how do you set the baud rate to 115200?

0 Bob Crosby over 7 years ago in reply to Vikram Jain

TI__Guru 72500 points

If you are running with VCLK=80MHz, then use the SPI Extended Prescale Register to set the SPI clock rate to VCLK/694. That gives 115273 baud, which 0.06% fast. Since the receiving device will resynchronize on each start bit, it will never notice the slight discrepancy.

0 Vikram Jain over 7 years ago in reply to Bob Crosby

Intellectual 485 points

Thank you that seems to work now :)

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TMS570LS0432: SPI to emulate UART transmit