[SOLVED] How to retarget printf to UART in SES(v5.50) with SEEGER Compiler and Runtime Library

kying · Jun 18th 2021, 5:02pm

Hello guys, i'm a student and i'm learning STM32. I used to programming in Keil5(MDK), but i met the SES few days ago and fell in love with it soon.

I met some troubles, i want to retarget printf to UART, if i import project from Keil and use the ARMCC, that will be very easy, the only thing i should do is "use the MircoLib and retarget printf to UART via some codes".
But if i Set Build Configurations to "Internal"(using the SEEGER Compiler/ Linker, Include Standard Libraries with SEGGER Runtime Library), i can't make it work

.i know that if i retarget printf to UART, the "Library I/O" shouldn't be setted to SEMIHOST(or RTT/SWO), so i set it to the "STD".
After that i followed the wiki,and found that:

SEGGER Wiki wrote:

When STD is selected as Library I/O, the user has to supply an implementation of int __SEGGER_RTL_stdout_putc(int c); which can be used to route character output to any resource, such as a UART or other terminal.

so i guess, i should set the "Library I/O = STD" and define the int __SEGGER_RTL_stdout_putc(int c) to retarget the printf().
And I did it,but i get a strange error: undefined symbol: __SEGGER_RTL_X_file_write
After many attempts, i couldn't find the reason, but to my surprise, if i set the options "Code > Compiler > Use Compiler Driver = NO-->YES", the error will gone, but printf() still not working

.
that's my code,trying to retarget printf to UART1, like what i done in keil, emm, and i'm using the STM32 HAL library yet.

C Source Code: retarget printf to UART

#if 1
//#pragma import(__use_no_semihosting)
int __SEGGER_RTL_stdout_putc(int ch)
{
HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
#endif

if you can help me, i would appreciate it very much! :thumbsup:

Forgive my poor English

~~

illishar · Jun 25th 2021, 8:40am

A valid question. I'll listen in as well.

SEGGER - Nino · Jul 28th 2021, 5:30pm

Hi,

Sorry for the delay in response.
There have indeed been changes to the RTL implementation here for the STD I/O.
As the error message suggests you need to supply an implementation of __SEGGER_RTL_X_file_write now.
This has been addressed in the documentation here:
wiki.segger.com/Embedded_Studio_Library_IO#STD

Best regards,

Nino

AxKe · Jul 29th 2021, 12:02pm

Hello to all,
I found yesterday the declacation to the __SEGGER_RTL_X_file_write() in corresponding __SEGGER_RTL.h.
So I included the following function in my project and it works.

C Source Code

int __SEGGER_RTL_X_file_write (__SEGGER_RTL_FILE *__stream, const char *__s, unsigned __len)
{
HAL_UART_Transmit(&huart1, __s, __len, 10);
return 0;
}

But i can't replay this yesterday, because my registration for this forum was approved today.
So I saw the new description for this issue form Nino today.

But I have further question:

What ist the definitin for the return value of __SEGGER_RTL_X_file_write(..)?

Kind regards

AxKe

SEGGER - Nino · Jul 29th 2021, 2:08pm

Hi AxKe,

Indeed the return values were not described.
We updated the Wiki accordingly.
wiki.segger.com/Embedded_Studio_Library_IO#STD

Keep in mind that if you retarget to e.g. a filesystem and if the disk returns that it is full, the return value for the write function would still be considered "OK".

Best regards,
Nino

AxKe · Jul 31st 2021, 6:54pm

Hello Nino,
thank you for your support and fast reply.

kind regards

AxKe

[SOLVED] How to retarget printf to UART in SES(v5.50) with SEEGER Compiler and Runtime Library

[SOLVED] How to retarget printf to UART in SES(v5.50) with SEEGER Compiler and Runtime Library

SEGGER Wiki wrote:

C Source Code: retarget printf to UART

C Source Code

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