;*************************************************************************************
;*********************** SECTION 1: FILTER LIBRARY *********************************** 
;*************************************************************************************
Thank you for trying C28x Software Collateral. 
Filter Library is installed in C:\TIDCS\C28\DSP_TBOX\FILTER directory.

Digital filters are a common requirement for digital signal processing systems. 
There are two types of digital filters: Finite impulse response (FIR) and infinite impulse
response (IIR) filters. Both the filter modules are available in the filter library. 

We have made available an ezFIR filter design package (MATLAB script) to interactively 
generate filter coefficients for the required frequency response characteristics.

 
IIR filter uses the cascade configuration of direct form II structured Second order section (SOS) 
that reduces sensitivity to coefficient quantization. The SOS抯 are commonly referred to as Biquads. 
The SOS coefficients generated by the MATLAB for given set of filter specification provides unity 
gain in the pass-band and attenuates the remaining frequency component. Though the input to output 
gain does not peak above unity, the intermediate node gain in the biquad sections would vary significantly 
depending on the filter characteristics. Hence, we have made a available a ezIIR filter design package 
(MATLAB script) that generates scaled second order coefficients without overflow issues in the 
intermediate nodes. 

The following table summarizes the set of modules that are available in this library.

FILTER LIBRARY

|===============|======================================================================|
|  Module Name  | Description                                                          |
|===============|======================================================================|
| FIR16         | Generic FIR Filter (16-bit implementation)                           |
|---------------|----------------------------------------------------------------------|
| IIR5BIQ16     | Cascade IIR filter (16-bit implementation)                           |
|---------------|----------------------------------------------------------------------|
| IIR5BIQ32     | Cascade IIR filter (32-bit implementation)                           |
|======================================================================================|
 

DOCUMENTATION:
|===============|======================================================================|
|  DOC          | DIRECTORY LOCATION                                                   |
|===============|======================================================================| 
|  MODULE DOC   | C:\TIDCS\C28\DSP_TBOX\FILTER\DOC\FILTER_MDL.PDF                      |
|---------------|----------------------------------------------------------------------|
|  ezFIR DOC    | C:\TIDCS\C28\DSP_TBOX\FILTER\DOC\EZFIR.PDF                           |
|---------------|----------------------------------------------------------------------|
|  ezIIR DOC    | C:\TIDCS\C28\DSP_TBOX\FILTER\DOC\EZIIR.PDF                           |
|======================================================================================|


Version History:
================
Version 0.9c dated 01/12/2002
=============================
1. Corrected comments in the files 

Version 0.9b dated 04/07/2004
=============================
1. 2 Const(PosSatVal:,NegSatVal) are defined in fir16.asm  
   If they are linked in different Pages, the Filter does not work. Fixed this bug


Version 0.9a dated 12/06/2003 
=============================
1. Some the math function had .ref being used in the *.asm, it is changed to .def 
   Because of this bug, compiler was reporting that the function name is not available.

2. Most of the functions did not clear the OVM flag at the end, it is modified.

3. ASP & NASP is been used within functions, we should not disturb the ASP bit.
   It is meant for only interrupt handler. Called function should not change this bit.