CCS/TMS320F28069: atan2 calculation

Mir Hossein Ghoreishi

Intellectual 490 points

Part Number: TMS320F28069
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hello,

On CCS V9.0.1, I imported "Example_2806xFPU_hardware" from C2000Ware 1.0.6.0.

Modified code:

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

#include "MATH.H"

    //
    // Calculate two atan2 equations.
    //
    y1 = 8247;
    y2 = -8247;
    m1 = .5;
    m2 = .6;
    x1 = 4847;
    x2 = -4847;

    b1 = atan2(y1,x1) *180.0/3.1415926536;
    b2 = atan2(y2,x2) *180.0/3.1415926536;

Compiled and executed but got wrong results.

After checking many parameters, I removed "rts2800_fpu32_fast_supplement.lib" from linker library list and the issue resolved:

What is wrong with the default setting?

With regards,

MHG

over 6 years ago

0 Lori Heustess over 6 years ago

TI__Guru* 92780 points

Dear MHG,

The FastRTS library leverages math tables within the ROM of the device. I suspect the linker command file does not have the right address. Devices ending in "M" or "F" i.e. F28069M and F28069F have the FPU tables at a different location than the other devices.

Please check the linker command file (file ending in .cmd) for the mapping of the FPUTABLES. The origin should match the documented ROM location for your device.

For F28069M or F28069F:

FPUTABLES   : origin = 0x3FD590, length = 0x0006A0      /* F28069M & F28069F devices FPU Tables in Boot ROM */

For all other F2806x:

FPUTABLES   : origin = 0x3FD860, length = 0x0006A0 	 /* all other F28906x devices FPU Tables in Boot ROM */

From the device TRM Boot ROM memory map section: (www.ti.com/lit/SPRUH18)

0 Lori Heustess over 6 years ago in reply to Lori Heustess

TI__Guru* 92780 points

A quick follow-up. I have filed a bug report against our SW for this issue.

Thank you
Lori

0 Mir Hossein Ghoreishi over 6 years ago in reply to Lori Heustess

Intellectual 490 points

Hello Lori,

Thank you for the explanation.
I checked the linker command file, it is system's default "28069_RAM_lnk.cmd" with no 'M' or 'F' but I see
FPUTABLES : origin = 0x3FD590, length = 0x0006A0
Which is wrong according to your explanation.
Compared it to the "f28069M_ram_lnk.cmd" and you can see that the FPUTABLES in these two files are the same.

This need an update in C2000WARE files.

With regards,
MHG

0 Mir Hossein Ghoreishi over 6 years ago in reply to Lori Heustess

Intellectual 490 points

BTW, in Figure 2-1 you referred above there is a typo, IQTABLES address is 0x3fdf00 not 0x3fdf000

0 Lori Heustess over 6 years ago in reply to Mir Hossein Ghoreishi

TI__Guru* 92780 points

Thank you for pointing that out, MHG. I will submit a correction for the documentation.

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CCS/TMS320F28069: atan2 calculation