PM0014 datasheet(42/46 Pages) STMICROELECTRONICS

42 / 46 page

Signal processing library functions

PM0014

42/46

Coefficients must be stored in memory as follow:

addr

Iir.CoeffPtr

----> b0

addr

Iir.CoeffPtr + 2 ----> b1

...

addr

Iir.CoeffPtr + 2 * (IirNumberCoeffs/2 - 1)---->

b(IirNumberCoeff/2)-1

addr

Iir.CoeffPtr + 2 * (IirNumberCoeffs/2)----> a0 = 0

addr

Iir.CoeffPtr + 2 * (IirNumberCoeffs/2 + 1) ----> a1

...

addr

Iir.CoeffPtr + 2 * (IirNumberCoeffs - 1)---->

a(IirNumberCoeff/2)-1

Assembly source

code:

iir2_q15_q15_q15.asm

Code size and cycles: Size: 130 bytes

Instruction Cycles: 36 + NbOutput * (17 + IirNumberCoeffs)

Test:

Two test cases are provided. For each test case, two files allow to

test the function: an input vector file (dirFilterX_q15_q15_q15.in)

and an output vector file (dirfilterX_q15_q15_q15.res). The

configuration is the following:

number of coefficients: 32

number of output samples: 201

To perform the test, initialize the Delay line[] to zero, then Coeff[]

and Input[] with the dirfilterX_q15_q15_q15.in file: the first values

are the coefficients of the filter and the rest of the values are the

input values. (See the example for declarations).

PM0014 Datasheet(PDF) 42 Page - STMicroelectronics