topic Re: Floating Point on KDS in Kinetis Design Studio

Floating Point on KDS

ciful — Thu, 08 Jan 2015 09:40:46 GMT

Good morning.

I'm using the sprintf function but it doesn't work with float and double type.

It works properly only with integer.

I found a lot of information on this problem, but referred to the codewarrior ide.

How it's possible to solve this in the kinetis dev system ?

Thanks.

Claudio

Re: Floating Point on KDS

Carlos_Mendoza — Thu, 08 Jan 2015 17:48:39 GMT

Hi Claudio,

Please take a look at the following post created by our colleague Erich Styger, it explains how to use printf() and scanf() with floating point:

printf() and scanf() with GNU ARM Libraries | MCU on Eclipse

Hope it helps.

Best regards!

Carlos

Re: Floating Point on KDS

larrykoos — Tue, 27 Jan 2015 23:50:50 GMT

Claudio,

Did you ever get this to work? I cannot get the approach described in the Erich Styger article referenced above to work because his comments are referencing newlib-nano, not newlib. Any help would be appreciated.

Thanks,

Larry

Re: Floating Point on KDS

matherinewang — Mon, 23 Nov 2015 05:58:50 GMT

Hello，

I have add -u _printf_float to the linker options to enable float/double support to printf/sprintf(), but still can not work with float, any other configuarion needed?

Re: Floating Point on KDS

BlackNight — Mon, 23 Nov 2015 07:35:38 GMT

Semihosting (and printf()) depends on the library used.

Have a look at

Semihosting with GNU ARM Embedded (Launchpad) and Kinetis Design Studio | MCU on Eclipse

Do not forget to use the -specs=rdimon.specs linker option.

I hope this helps,

Erich

Re: Floating Point on KDS

syedidris — Thu, 03 Dec 2015 11:13:05 GMT

I did same as matherin,

but not getting float printing, I getting error like this,

plz anyone clarify this doubt.

Re: Floating Point on KDS

DavidS — Fri, 04 Dec 2015 18:31:25 GMT

Hi Syed,

What processor are you using? Looking at the errors it seems like KL03.

The above post were asking for printf/scanf with floating point support. Is that what you want too?

If yes attached is an example project for the FRDM-KL03Z.

Note that KL03 on the Freedom board is limited to 32KByte flash and very limited to 2KByte of SRAM.

Because of that I had to increase the compiler optimization to get the linker to work.

Regards,

David

Re: Floating Point on KDS

syedidris — Sat, 05 Dec 2015 10:58:30 GMT

David sir,

Thanks for your reply.

Actually I am a beginner, and yes you are right, I am using KL03 processor.

And I don't know about processor expert. I am trying to learn with demo codes provided with KDS3.0.0 IDE. when I am trying to print the float value like,

float a=2.4;

PRINTF("%f",a);

I am getting output as ' f ' only, so I searched on forum and enabled the option -u_printf_float with the following:

Properties -> C/C++ build -> Settings -> Cross ARM C Linker -> Miscellaneous -> Use float with nano printf

But, no change in the behavior of printf.

I will be thankful to you if you solve my problem

Re: Floating Point on KDS

DavidS — Mon, 14 Dec 2015 21:56:18 GMT

Hi Syed,

Please open your Properties of your project and add the following SCANF_FLOAT_ENABLE and PRINTF_FLOAT_ENABLE....recompile and run again.

Regards,

David