How can i use printf(using uart) on mpc5744

[fyw]

The platform is S32(S32 Design Studio for Power Architecture, Version 1.0 build 151127), now i can use uart send data to the serial port terminal. if i want to use "printf" with uart, how should i configure the project? 

Thank you very much!

  UART_SendData(&LINFlexD_X ,0xaa);  /* this is ok now*/

  printf ("Characters: %c %c \n", 'a', 65);    /*build err here  Description Resource Path Location Type

S32DS/e200_ewl/EWL_C/src/stdio/printf.c undefined reference to `__pformatter' Example_Base  line 44 C/C++ Problem

*/

[gary1232]

hi,fyw

can you gave me  your example.... (use uart send data to the serial port terminal)

cause i try many day... still not working for this functions.

please, thanks....

[fyw]

It already look like this:   but it still report the err  

.stack (NOLOAD) : ALIGN(16)

    {

      __HEAP = . ;

      . += __HEAP_SIZE ;

      __HEAP_END = . ;

      _stack_end = . ;

      . +=  __STACK_SIZE ;

      _stack_addr = . ;

      __SP_INIT = . ;

      . += 4;

    } > m_data

Secondly, i find in the uart_console_io.c file,  the three include file(below) cann't be found.  I think this uart_console_io.c file is not suitable for  newlib

#include <ansi_parms.h>

#include "console_io.h"

#include <ewl_misra_types.h>

[martin_kovar]

Hi,

use the following code for .stack section

.stack (NOLOAD) : ALIGN(16)

    {

      __HEAP = . ;

      _end = . ;

      end = . ;

      . += __HEAP_SIZE ;

      __HEAP_END = . ;

      _stack_end = . ;

      . +=  __STACK_SIZE ;

      _stack_addr = . ;

      __SP_INIT = . ;

      . += 4;

    } > m_data

Regards,

Martin

[fyw]

Thank you Martin Kovar! This works!

But i still have another problem. Since i choose the newlib, i find that the "uart_console_io.c" file doesn't work well.   "uart_console_io.c" file has three include file :

#include <ansi_parms.h>

#include "console_io.h"

#include <ewl_misra_types.h>

The three file could not be found. So add the path(you can see in the pic below)

After that the project build OK. But when the program runs, i find that the printf can not send anything.

I put a breakpoint at function "__write_console", and find that the program doesnot stop at the function "__write_console".

So i guess that the printf does not call "__write_console". 

Need other settings?

[martin_kovar]

Hi,

sorry for delay, but I have no experience with printf function using newlib library yet. Please give me a time, I will investigate, how it works and I will write you back if it is possible to use it.

Regards,

Martin

[fyw]

Thank you very much!

[martin_kovar]

Hi,

at first, I would like to apologize for my previous claim. EWL library supports formaters like %d or %f. There is completely different issue, which can be easily fixed.

Add the following line to the Linker flags:

-Xlinker --undefined=__pformatterFP -Xlinker --defsym=__pformatter=__pformatterFP

Now it will work correct.

Regards,

Martin

[fyw]

Thank you very much! It works!

I wander is there any book or document introduce about the "linker" thing of S32?

for example  i do not know the exact meaning of the following two lines(list follow) and also the "-Xlinker --undefined=__pformatterFP -Xlinker --defsym=__pformatter=__pformatterFP"

.stack (NOLOAD) : ALIGN(16)

    {

      __HEAP = . ;

      _end = . ;???????????????

      end = . ;???????????????

      . += __HEAP_SIZE ;

      __HEAP_END = . ;

      _stack_end = . ;

      . +=  __STACK_SIZE ;

      _stack_addr = . ;

      __SP_INIT = . ;

      . += 4;

    } > m_data

[martin_kovar]

Hi,

S32DS uses gcc compiler and linker and these are under GNU GPL license. So the documentation is public, please look at the following URLs.

https://sourceware.org/binutils/docs/ld/

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&sqi=2&ved=0ahUKEwjWrK...

About "-Xlinker --undefined=__pformatterFP -Xlinker --defsym=__pformatter=__pformatterFP", it is little bit complicated, but I will try to explain.

When you call printf with some formatter, for example printf("%d",0xAA), function int_t _EWL_CDECL printf from printf.c file is called. In this function, __pformatter function is called. But this __pformatter calls function from stdio_api.h, which is not correct. Correct function, which has to be called is function __pformatterFP placed in  __printformat.c file.

So the linker flag says that there is undefined symbol __pformatterFP (part -Xlinker --undefined=__pformatterFP) and define symbol __pformatter as a __pformatterFP (part -Xlinker --defsym=__pformatter=__pformatterFP ). So from my point of view, symbol __pformatter is replaced by __pformatterFP. Now correct function is called and the program could be compiled.

About the end symbols, please look at the following URL:

libgloss/libnosys/sbrk.c - native_client/nacl-newlib - Git at Google

You can see that line 10 declares extern char  end; /* Set by linker. */. This is the symbol which has to be add to the linker file.

I hope it helps you a little bit, but if you have any other questions, please feel free to write me back.

Regards,

Martin

[fyw]

Thank you very much!!!

[martin_kovar]

Hi,

please look at the following example:

Example MPC5744P PinToggleStationery S32DS

If you have any other questions, please feel free to write me back.

Regards,

Martin

[fyw]

Thank you very much!

now i find a strange problem

if i write like this:

printf("Best Regards, Technical Information Center\r\n");   --->It's OK!

but if i write like this:

printf("Best Regards %d, Technical Information Center\r\n", 0xAA);   ---> it reports an err

"S32DS/e200_ewl/EWL_C/src/stdio/printf.c undefined reference to `__pformatter' Example_Base  line 44 C/C++ Problem"

i find even in the project"Example MPC5744P PinToggleStationery S32DS", it also reports the same err

[martin_kovar]

Hi,

EWL library does contain only printf function, which accepts const char * parameter. If you want to pass any other parameters like integer, float, etc.. you have to use NewLib library. This library can be chosen while you create a project (in project wizard) or you can change it in project settings (see figure below)

Regards,

Martin

[fyw]

${VLE_NEWLIB_DIR}/newlib

-------------------------- where is this path?  I can not find in my computer

[fyw]

Thank you Martin Kovar ,

I have tried this

(learn form this  Linker errors when using the "new" operator )

but i meet the same problem " sbrk.c:21: undefined reference to `end' "

the author say " changed the heap size and added an "end" definition at the beginning of the heap section, it works just fine."

I donot know how "added an "end" definition at the beginning of the heap section"?  could you help me for that?  thank you very much!

[bdn]

Hi,

you have to change your linke file. In your project folder direct to Project_Settings and edit section.ld

Section .stack should look like that:

	.stack (NOLOAD) : ALIGN(16)
	{
	__HEAP = . ;
	. += __HEAP_SIZE ;
	__HEAP_END = . ;
	_stack_end = . ;
	. +=  __STACK_SIZE ;
	_stack_addr = . ;
	__SP_INIT = . ;
	. += 4;
	} > m_data

Regards,

Bernhard