ADAU1452 HexArray format in compiler XML output

Hello all,

I use the xml-file which is generated by SigmaStudio to create an update file for our product which includes an ADAU1452 DSP and a microcontroller, connected with a I2C bus. In this DSP, FIR filters are implemented and the microcontroller reads the FIR coefficients from an external eeprom and writes them into the DSP. So far, no troubles :-)

To write the FIR coefficients into the right places in the DSP, I include the _PARAM.h file (which is also generated by the SigmaStudio compiler) in the microcontroller program, to obtain the various I2C addresses of the used DSP components (cells). Both the xml file and the _PARAM.h file give me a I2C starting address of a FIR filter, say 2350. But this seems to be the last coefficient of the fir filter. Is that correct?

When I create a 5-tap fir filter in Sigma Studio and hit the 'Table' button of the cell, and enter '1', '2', '3', '4' and '5' as coeffcient 1,2,3,4 and 5, they are stored reversed in both the xml data node and in the _PARAM.h header file:

entered in Sigma Studio

XML file snippet:

and in the headerfile:

You can see, the array elements are a reversed representation of the coefficients entered in SigmaStudio.

That is no problem, but what if I load a coefficient table, generated with a tool like RePhase, or the one downloaded from mds.com Do I have to reverse the coefficient array of these tools too? It does not seem so (I tested a few fir filyer designs), but, if not, why is the order of entered coefficients (in Sigma Studio) reversed by the compiler in it's output?

With kind regards,

Reini

Edit Notes
'a external' replaced by 'an external'

[edited by: Reini at 2:21 PM (GMT 0) on 28 Apr 2020]

Audio Signal Processors

adau1452

reverse

SigmaDSP Audio Processors

fir