TMS320C6748: Problem with UART Basic Example (TMDSLCDK6748)

BradS

Part Number: TMS320C6748
Other Parts Discussed in Thread: OMAPL138, TMDSLCDK6748

I have created the PDK examples from the distribution [processor_sdk_rtos_omapl138_6_03_00_106 and pdk_omapl138_1_0_11] (not easy but accomplished thankyou Embedded Advantage guys for the assist). Now I want to do something with the TMDSLCDK6748 evaluation module. To me serial is an easy communication to test in that you can use a PC to verify that the unit is generating the correct data. The PDK had three examples, I chose to work with is the "UART_BasicExample_lcdkOMAPL138_c674xExampleProject". With this project the initialization is done with the Board_init() function setting the BOARD_INIT_PINMUX_CONFIG | BOARD_INIT_MODULE_CLOCK | BOARD_INIT_UART_STDIO to configure the serial port as the stdio input/output location. Then, in a task, the program uses the UART_puts() function to transmit a string of data. It all sort of works but the transmission is not at any standard baud rate that I can determine. My questions are:

1) What is the baud rate for this port?
2) How is the uart's configuration set?
3) How can I change the uart configuration?

over 2 years ago

0 Andrew Shutzberg over 2 years ago

TI__Intellectual 2360 points

Hello Brad,

Thank you for your question. I am currently consulting with my colleagues about this topic, and I hope to have an answer/update for you within the next 1-2 business days. Thank you for your patience, and feel free to post any additional details/developments for consideration here.

Best regards,

Andrew

0 Andrew Shutzberg over 2 years ago

TI__Intellectual 2360 points

Hello Brad,

Upon checking our records I found a some similar E2E posts that could help you troubleshoot this particular example for this device:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/654445/tms320c6748-not-able-to-build-uart-processor-sdk-example

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/811853/rtos-tmdslcdk6748-uart-callback-mode-reads-the-data-only-one-time

Do these posts assist with the problem you are facing?

Best regards,

Andrew

0 BradS over 2 years ago in reply to Andrew Shutzberg

Prodigy 160 points

Andrew,

Thanks for the response. However, neither of the links address my issue. The first link you provided is about the extraction and building of the program. I have already accomplished the extraction of the example and have successfully extracted and compiled the example. The second link is about the reading of data sent TO the uart inside the C6748. Right now I am just trying the get a PC to decode transmissions FROM the C6748 uart.

To restate my issue, I am trying to understand where in the code and by what method the example project ("UART_BasicExample_lcdkOMAPL138_c674xExampleProject") set the baud rate of the uart? I am looking for this information so I can better understand the way the uart getting configured and by extension how we could properly configure the uart for use in our project.

Thanks in advance for your assistance,

Brad

0 Andrew Shutzberg over 2 years ago in reply to BradS

TI__Intellectual 2360 points

Hello Brad,

Thank you for your patience, I relayed your clarification to the team, and this is the response I got:

"You can start from the main() of this example to get to UART LLD: main() -> Board_init() in pdk_omapl138_1_0_11\packages\ti\board\src\evmK2G\evmK2G.c -> Board_uartStdioInit() in pdk_omapl138_1_0_11\packages\ti\board\src\evmKeystone3\board_lld_init.c -> UART_stdioInit() in pdk_omapl138_1_0_11\packages\ti\drv\uart\src\UART_stdio.c

Then UART_Params_init() uses the default parameters (defined in uart\src\UART_drv.c). You can change the parameters before calling UART_open().

Looking at the default UART parameters, UART_defaultParams, the baud rate for this port is 115200."

Was this the information you were looking for?

-Andrew

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TMS320C6748: Problem with UART Basic Example (TMDSLCDK6748)