CCS/TMS320C5515: TMS320C5515 hwafft

Hi SMART,

Either delete hwafft.asm from your project or exclude it from your project build (right click on file).

At the end of your .cmd file (after the MEMORY and SECTIONS blocks), add the following ROM locations for the HWAFFT functions - thsse are specific to C5505 and C5515 PG2.0.

/* HWAFFT Routines ROM Addresses */
/* C5505/C5515 (PG 2.0) */
_hwafft_br         = 0x00ff6cd6;
_hwafft_8pts     = 0x00ff6cea;
_hwafft_16pts     = 0x00ff6dd9;
_hwafft_32pts     = 0x00ff6f2f;
_hwafft_64pts     = 0x00ff7238;
_hwafft_128pts     = 0x00ff73cd;
_hwafft_256pts     = 0x00ff75de;
_hwafft_512pts     = 0x00ff77dc;
_hwafft_1024pts    = 0x00ff7a56;

If you had mapped the hwafft.asm functions into DARAM, the performance might be better when called from ROM as it frees the DARAM up for the HWAFFT data accesses (which should be in DARAM).

Running these routines from ROM will save your RAM for other code or data storage.

However, pay attention to Errata 2.1.9 HWAFFT Data and Scratch Pointers Copied as 16-Bit Instead of 23-Bit
Instead of using extended aux registers, the HWAFFT software stored in ROM uses (non-extended) aux registers - copying only the lower 16-bits of a potentially 23-bit address. The errata provides a workaround.

One easy way to workaround this errata is to use the small memory model instead of large or huge memory models. Then all accesses will use 16-bits and the errata is worked around.

C5515 Errata:  www.ti.com/.../sprz308

Don't forget to align your data and scratch buffers in memory as demonstrated in the abstract section of FFT Implementation on the TMS320VC5505, TMS320C5505, and TMS320C5515 DSPs (Rev. B)
http://www.ti.com/lit/pdf/sprabb6

After you build the project, you can open the .map file to confirm the HWAFFT routines are being called from ROM instead of RAM. It should show up like below:

00ff7a56                _hwafft_1024pts
00ff73cd                _hwafft_128pts
00ff6dd9                _hwafft_16pts
00ff75de                _hwafft_256pts
00ff6f2f                  _hwafft_32pts
00ff77dc                _hwafft_512pts
00ff7238                _hwafft_64pts
00ff6cea                _hwafft_8pts
00ff6cd6                _hwafft_br

Hope this helps,
Mark

Hi Mark,

I have edited c5515.cmd file (after the MEMORY and SECTIONS blocks), add the following ROM locations for the HWAFFT functions. But compiler cannot success...

Error message :

unresolved symbol _hwafft_512pts, first referenced in ./fastdct.obj

unresolved symbol _hwafft_br, first referenced in ./fastdct.obj

What is my problem root?