TMS320F280049: C I/O functions to output the SCI peripheral on C28x

Olivier Monnier

Prodigy 325 points

Part Number: TMS320F280049

Hi,

one designer is trying to redirect standard IO (printf/scanf) to UART on the C28x.

Some some information on this topic was found here:

https://software-dl.ti.com/ccs/esd/documents/sdto_cgt_tips_for_using_printf.html

and more information about the low level functions in chapter 8.2 The C I/O Functions of the TMS320C28x Optimizing C/C++ Compiler User’s Guide.

Is there an easier way to do this? Designer is used to rewrite the fputc() and fgetc() functions to direct characters to and from a software buffer that in its turn is directed to and from the uart peripheral.

Questions:

Is it necessary to follow the procedure or would rewriting fputc and fgetc also work?
Is there sample code for either option?

thanks

Olivier

over 4 years ago

0 George Mock over 4 years ago

TI__Guru**** 251120 points

Olivier Monnier said:
Is it necessary to follow the procedure or would rewriting fputc and fgetc also work?

Following the procedure is the only documented method. I'm aware that others have just changed fputc and fgetc. But that is a less robust solution.

Olivier Monnier said:
Is there sample code for either option?

Please see the article RAMDISK: A Sample User-Defined C I/O Driver.

Thanks and regards,

-George

0 GregM over 4 years ago in reply to George Mock

TI__Expert 5365 points

Some feedback from one of our experts on the subject:

Does not recommend rewriting fputc and fgetc. Says that fputc is not an easy function to write, whereas "write" is super-duper easy to write.

Instead, use the add_device method. Demo attached.

Another way is to override the seven low-level IO functions. Take the file uart_drv.c and rename all of the functions from UART_open to open, UART_close to close, etc, and drop it into the application.

Thanks
Greg

uart_drv.zip

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TMS320F280049: C I/O functions to output the SCI peripheral on C28x