How to fix the mbed-printf Keil uV5 hardfault issue ?

[T J]

Posted on January 13, 2017 at 21:35

Hi,

I have finally dragged everything offline into Keil and it now compiles

but instantly goes into hardfault caused by the printf.

How do we fix this issue ?

[Tesla DeLorean]

Posted on January 14, 2017 at 04:36

You'd have to ensure the data goes some where rather than trap with a BKPT or SWI

//****************************************************************************
// Hosting of stdio functionality through USART2
//****************************************************************************
 
#include <rt_misc.h>
 
#pragma import(__use_no_semihosting_swi)
 
struct __FILE { int handle; /* Add whatever you need here */ };
FILE __stdout;
FILE __stdin;
 
int fputc(int ch, FILE *f)
{
 while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);
 
 USART_SendData(USART2, ch);
 
 return(ch);
}
 
int fgetc(FILE *f)
{
 char ch;
 
 while(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET);
 
 ch = USART_ReceiveData(USART2);
 
 return((int)ch);
}
 
int ferror(FILE *f)
{
 /* Your implementation of ferror */
 return EOF;
}
 
void _ttywrch(int ch)
{
 while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);
 
 USART_SendData(USART2, ch);
}
 
void _sys_exit(int return_code)
{
label: goto label; /* endless loop */
}
 
//****************************************************************************
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[T J]

Posted on January 15, 2017 at 00:31

Hi Clive, excellent.

I am trying to implement the same now, but the syntax kills me.

The resulting code is attached but still hard faults because I attempt to write to STDOUT.

Compile Errors

[FILE __stdout] warning: #2681-D: name linkage conflicts with previous declaration of variable 'std::__stdout' (declared at line 138 of 'C:\Keil_v5demo\ARM\ARMCC\Bin\..\include\stdio.h')

error: #734: function 'fputc(int, std::FILE *)' conflicts with using-declaration of function 'std::fputc(int, std::FILE *)'

should there be a .h declaration of FILE ? is it nStream ?

I have implemented mostly of what you suggested, but I cannot work out the syntax to redirect stdin/stdout.

which is required to fix the printf hardfault issue in Keil when using mbed.

Please see attached skeleton uV5 project without the target or mbed

my target is a STM32F091

________________

Attachments :

Nucleo_printf.uvguix.zip : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HysO&d=%2Fa%2F0X0000000bF1%2Fg3UhhshhqGQeO5bXWAi7HxCnc1RGWOWsqgXAjrQwB6U&asPdf=false