ADAV4601 System Design Document Confidential Information
Rev.1 August 2009 Analog Devices Page 46
Every block (volume, filter, mux, etc) available in SigmaStudio is a cell and is defined in the params.params file
generated by SigmaStudio. An example of a cell defined in params.params, in this case a general 2
nd
order low
pass filter with a cut off of 1kHz, is shown below.
Where:
Cell Name: Indicates that the following parameter information belongs to that cell.
Parameter Name: A cell may have more than one parameter associated with it and this identifies it.
Parameter Address: The location of the parameter in parameter memory in decimal.
Parameter Value: The value of the parameter in decimal.
Parameter Data: The value of the parameter in hexadecimal 5.23 format.
Cell Name = Gen Filter1
Parameter Name = EQ1940Single10B1
Parameter Address = 0
Parameter Value = 0.00408828258514404
Parameter Data :
0X00 , 0X00 , 0X85 , 0XF7 ,
Cell Name = Gen Filter1
Parameter Name = EQ1940Single11B1
Parameter Address = 1
Parameter Value = 0.00817668437957764
Parameter Data :
0X00 , 0X01 , 0X0B , 0XEF ,
Cell Name = Gen Filter1
Parameter Name = EQ1940Single12B1
Parameter Address = 2
Parameter Value = 0.00408828258514404
Parameter Data :
0X00 , 0X00 , 0X85 , 0XF7 ,
Cell Name = Gen Filter1
Parameter Name = EQ1940Single11A1
Parameter Address = 3
Parameter Value = 1.8951700925827
Parameter Data :
0X00 , 0XF2 , 0X94 , 0XEF ,
Cell Name = Gen Filter1
Parameter Name = EQ1940Single12A1
Parameter Address = 4
Parameter Value = -0.911523461341858
Parameter Data :
0X0F , 0X8B , 0X53 , 0X33 ,
Custom Flow Example:
The example that follows goes through the steps required to change the filter cut off to 2kHz.
1.
The system controller provides the filter coefficients, b
0
b
1
b
2
a
1
a
2
, in 5.23 format.
b
0
= 0.0156048536300659 -> 0x0001FF57
b
1
= 0.0312097072601318 -> 0x0003FEAE
b
2
= 0.0156048536300659 -> 0x0001FF57
a
1
= 1.76945173740387 -> 0x00E27D65
a
2
= -0.831871271133423 -> 0x0F95853E
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