TMS320F28035: Fixed point sfra

Hey Jack,

1. SFRA can support IQ24 format, but amplitude has to be in range of [-1, 1] of IQ26 after conversion.

2. As Default support is IQ26, GUI is displaying amplitude value in IQ26 format, and it should not affect SFRA Functionality when you are using in IQ24 format.

Can you also check IQ20 / IQ22 and see the values in GUI reflected in IQ26 format, just for cross verification? 

Hi Shashank,

Regarding to below code, what I expected is that inject_ref = vl_Vars.Ref + amplitude*cos(theta);

int32 inject_ref = SFRA_IQ_INJECT(vl_Vars.Ref);

And my vl_Vars.Ref is using IQ24 formate, so how to config the amplitude?

and what's exact IQ formate for amplitude*cos(theta)? IQ26?

Here are the GUI display value for IQ20(0.01) and IQ22(0.01), it always show the value as IQ26

In addition, I found that the --library=rts2800_ml.lib<fs_mpy.obj> has to be replaced by --library=rts2800_ml.lib<fs_mpy28.asm.obj> to remove the warning, is it correct?                              

Jack Tan80 said:

Here are the GUI display value for IQ20(0.01) and IQ22(0.01), it always show the value as IQ26

By Default, amplitude uses IQ26 Format but we can configure in IQ24 Format too.
You can proceed by configuring amplitude in IQ24 format, as vl_Vars.Ref is using IQ24 format.

Let me loop in our rts Library expert to comment on this.

Jack,

Can you tell me what warning you are referring to? That was not clear from your message.

Also, which software and version are you using, and where are you finding this SFRA user's guide?

Thanks,

Sira

Hi Sira,

I'm using the sfra user's guide as below link, and page 14 have the link cmd, --library=rts2800_ml.lib.

https://www.ti.com/lit/ug/spruhz5a/spruhz5a.pdf?ts=1691476832463&ref_url=https%253A%252F%252Fwww.google.com%252F 

And the warining is

Description Resource Path Location Type
#10068-D no matching section F28035_CLA_C.cmd /F2803xBD029PLLC_APP/source/common/cmd line 139 C/C++ Problem

After using --library=rts2800_ml.lib<fs_mpy28.asm.obj> instead, the warning is gone.

Regards,

Jack

I presume you are trying to include the SFRA lib into your own project? You are not using the existing F2803x SFRA example in ControlSUITE, correct?

What version of the compiler are you using? It's possible the compiler version you're using doesn't have a corresponding object file.

What made you use fs_mpy28.asm.obj? Did the compiler emit that suggestion on the build?

Thanks,

Sira

Hi Sira,

Yes, this is my project that integreate sfra lib. 

The compiler is TI v22.6.0.LTS

The .map file helps me to use fs_mpy28.asm.obj, please see below screenshot from map file.

Regards,

Jack

Ok, I understand, if you use fs_mpy.obj in the linker cmd file, it gives you a warning, and the .map file mentions fs_mpy28.asm.obj. And if you change to that, it fixes the warning. I can check with the compiler team as to what the differences are.

Sira,

Another question about fixed point sfra result, what the IQ formate for mag and phase vector table? IQ24 or IQ26?

Sometimes I need to use CAN to read sfra result from device.

Regardds,

Jack

Jack,

My understanding is that the format is IQ16.

Thanks,

Sira

Hi Sira,

Regards to this warning, how was the compiler team say? May I have some update about this?

Regards,

Jack