fir_top_mlab.m

Altera FPGA CPLD设计高级篇电子书籍

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%THIS IS A WIZARD GENERATED FILE. DO NOT EDIT THIS FILE!                                                                                
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%---------------------------------------------------------------------------------------------------------                              
%This is a filter with variable coefficients combine with interpolatipon and decimation                                                 
%Please input:                                                                                                                          
%data vector: 		stimulation(1:n)                                                                                                 
%coefficient matrix:	coef_matrix(n * interpolation_factor,m). n is the input data length, m is the coefficients length.              
%                       coef_matrix(1,:) coressponds to coefficient at time unit 1.                                                     
%                       coef_matrix(2,:) coressponds to coefficient at time unit 2.                                                     
%                                                                                                                                       
%                       coef_matrix(n,:) coressponds to coefficient at time unit n.                                                     
%                                                                                                                                       
%FILTER PARAMETER                                                                                                                       
%Input Data Type:	Signed
%Input Data Width:	12
%MSB Truncation Bits: 0
%MSB Truncated
%MSB Satuated
%LSB Truncation bits: 0
%LSB Truncated
%LSB Rounded
%OUTPUT Data Width:   27
%-----------------------------------------------------------------------------------------------------------

	%MegaWizard Scaled Coefficient Values
	function  output = fir_top_st_mat (stimulation, output)
	coef_matrix=[363 377 391 405 418 430 441 452 461 471 479 486 493 497 502 506 508 510 511 510 508 506 502 497 493 486 479 471 461 452 441 430 418 405 391 377 363 ];
  
	INTER_FACTOR = 1;
	DECI_FACTOR = 1 ;
	MSB_RM = 0;
	MSB_TYPE = 0;
	LSB_RM = 0;
	LSB_TYPE = 0;
	FIR_WIDTH = 27;
	OUT_WIDTH = FIR_WIDTH - MSB_RM - LSB_RM;
	DATA_WIDTH= 12;
            
	data_type= 1;

        % check size of inputs.
        [DX,DY] = size(stimulation);
        [CX,CY] = size(coef_matrix);
        
        %fill coef_matrix to length of data with the latest coef set
        if (CX < DY * INTER_FACTOR)
            for i= CX +1:DY * INTER_FACTOR
                coef_matrix(i,:) = coef_matrix(CX,:);
            end
        end

        %check if input is integer
       	int_sti=round(stimulation);
	    T = (int_sti ~= stimulation);
	    if (max(T)~=0)
	        fprintf('WARNING : Integer Input Expected: Rounding Fractional Input to Nearest Integer...\n');
	    end
	    
	    %Input overflow check
	    switch  data_type
	    case 1
	        %set max/min for signed
	        max = 2^(DATA_WIDTH-1)-1;
	        min = -max-1;
	    case 2
	        %set max/min for unsigned
	        max = 2^DATA_WIDTH-1;
	        min = 0;
	    end

	    %Saturating Input Value
	    a=find(int_sti>max);
	    b=find(int_sti<min);
	    if (~isempty(a)|~isempty(b))
	 	    fprintf('WARNING : Input Amplitude Exceeds MAXIMUM/MINIMUM allowable values - saturating input values...\n');
	            lena = length (a);
	            lenb = length (b);
	            for i =1:lena
	        	    fprintf('%d > %d \n', int_sti(a(i)), max);
			        int_sti(a(i)) = max;
		        end
		    for i =1:lenb
			    fprintf('%d < %d \n', int_sti(b(i)), min);
			    int_sti(b(i)) = min;
		    end
	    end
        
	    % Add interpolation
   	    inter_sti = zeros(1, INTER_FACTOR * length(int_sti));
	    inter_sti(1:INTER_FACTOR:INTER_FACTOR * length(int_sti)) = int_sti;

        
        for i = 1 : DY *INTER_FACTOR
    	    coef_current = coef_matrix(i,:);
            output_temp(i) = simp_adaptive (inter_sti, coef_current, i);
        end
	% Truncate output
	len1 = length(output_temp);
	
	    switch  LSB_TYPE
	    case 0
	        %truncate
            out_dec = bi_trunc_lsb(output_temp,LSB_RM,FIR_WIDTH);
	    case 1
	        %round
            out_dec = bi_round(output_temp,LSB_RM, FIR_WIDTH);
	    end
        
 	    switch  MSB_TYPE
	    case 0
	        %truncate
            out_dec = bi_trunc_msb(out_dec,MSB_RM,FIR_WIDTH-LSB_RM);
	    case 1
	        %round
            out_dec = bi_satu(out_dec,MSB_RM, FIR_WIDTH-LSB_RM);
	    end
 	   
    	% choose decimation output in phase=DECI_FACTOR-1  
     	if(DECI_FACTOR == 1)
     		output = out_dec;
     	else
     		output = out_dec(DECI_FACTOR:DECI_FACTOR:len1);
 	    end 
 	      
  	function[output, outindex] = simp_adaptive (int_sti, coef_current, data_index, output)
	%Simulation is the whole input sequence
	%coef_current is the current coefficient set
	%data_index gives the last data to use
	%outputs are the sum of input and coef multiplication
	%outindex is the next data_index
   
	sti_current = zeros(length(coef_current),1);
	
	data_length = length(int_sti);
	
	%Check data index
	if (data_index > data_length)
		fprintf('ERROR: DATA INDEX IS LARGER THAN DATA LENGTH!!!\n');
		break;
	end
	for i = 1: length(coef_current)
	   if ((data_index -i+1)>0 & (data_index - i+1)<=data_length)
	      sti_current(i,1) = int_sti(data_index - i+1);
	   end
	end
	
	outindex= data_index+1;
	output = coef_current * sti_current;
	% end of function simp_adaptive

	function output = bi_round(data_in,LSB_RM,ORI_WIDTH, output)
	% LSB_RM is the bit to lose in LSB
	% ORI_WIDTH is the original data width
	data = round (data_in / 2^LSB_RM);
	output = bi_satu(data,0,ORI_WIDTH - LSB_RM);
	%end of function bi_trunc_lsb
	
	function output = bi_trunc_lsb(data_in,LSB_RM,ORI_WIDTH, output)
	% LSB_RM is the bit to lose in LSB
	% ORI_WIDTH is the original data width
	%2's complement system
	output = bitshift(2^ORI_WIDTH*(data_in<0) + data_in, -LSB_RM) - 2^(ORI_WIDTH-LSB_RM) *(data_in<0);
	% end of function bi_round
	
	function output = bi_trunc_msb(data_in,MSB_RM,ORI_WIDTH, output)
	% MSB_RM is the bit to lose in LSB
	% ORI_WIDTH is the original data width
	%2's complement system
	data = 2^ORI_WIDTH * (data_in < 0)+ data_in;
	erase_num = 2^(ORI_WIDTH - MSB_RM) - 1;
	data = bitand(data, erase_num);
	output = data - 2^(ORI_WIDTH - MSB_RM)*(bitget(data,ORI_WIDTH - MSB_RM));
	%end of bi_trunc_msb
	
	function output = bi_satu(data_in,MSB_RM,ORI_WIDTH, output)
	% MSB_RM is the bit to lose in LSB
	% ORI_WIDTH is the original data width
	%2's complement system
	max = 2^(ORI_WIDTH - MSB_RM -1)-1;
	min = 2^(ORI_WIDTH - MSB_RM -1)*(-1);
	data_in(find(data_in > max)) = max;
	data_in(find(data_in < min)) = min;
	output = data_in;
	%end of bi_satu