section 7 - Index of

All coefficients are divided by 2:w( n )/2=x( n)/2-ai 1/2*w( n-1 )-ai2/2*w( n-2)y( n )/2=w( n )/2+bi 1/2*w( n-1 )+bi2/2*w( n-2)X Memory OrganizationwN(n-1) Data + 2*nsec - 1wN(n-2)w1 (n-1)RO'" w1 (n-2) DataY Memory Organizationb1 N/2 Coef. + 4*nsec - 1b2N/2a1N/2a2N/2b11/2b2112a11/2R4.. a21/2 Coef.,.*********************************************************************************************************************initialization,.*************************************nsec equ 4start equ $40data equ 0coef equ 0input equ $ffeOoutput equ $ffe1igain equ 0.5ori #$08,mr ;set scaling modemove #data,rO ;point to filter statesmove #coef,r4 ;point to filter coefficientsmove #2*nsec -1 ,mOmove #4*nsec -1 ,m4move #igain,y1 ;y1 =initial gainopt ccfilter loop: 4*nsec + 9,.*********************************************************************movep y:input,yOmpy yO,y1,a x:(rO) +,xO y:(r4)+,yO;getsample;xO=1st section w(n-2),yO=ai2/2do#nsec,end_cellmac -xO,yO,a x:(rO) -,x1 y:(r4) +,yOmacr -x1,yO,a x1 ,x:(rO) + y:(r4) +,yOmac xO,yO,a a,x:(rO)+ y:(r4) +,yOmac x1,yO,a x:(rO) +,xO y:(r4) +,yO;do each section;x1 =w(n-1 ),yO=ai1/2;push w(n-1) to w(n-2),yO=bi2/2;push w(n) to w(n-1 ),yO=bi1/2;next iter:xO=w(n-2),yO=ai2/2end_cellrnd a ;round resultmovep a,y:output ;output sample,.****************************************************************************************endFigure 8-3 8-Pole 4-Multiply Cascaded Canonic IIR Filter (Sheet 2 of 2)