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[/] [cic_core_2/] [trunk/] [rtl/] [verilog/] [cic_d.sv] - Blame information for rev 9

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1 7 Juzujka 
module cic_d
2 
/*********************************************************************************************/
3 
#(
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        parameter INP_DW = 18,                  ///< input data width
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        parameter OUT_DW = 18,                  ///< output data width
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        parameter CIC_R = 100,                  ///< decimation ratio
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        parameter CIC_N = 7,                    ///< number of stages
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        parameter CIC_M = 1,                    ///< delay in comb
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        parameter SMALL_FOOTPRINT = 1   ///< reduced registers usage, f_clk / (f_samp/CIC_R)  > CIC_N required
10 
)
11 
/*********************************************************************************************/
12 
(
13 9 Juzujka 
        input                                                           clk,                    ///< input clock
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        input                                                           reset_n,                ///< input reset
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        input                                                           clear,                  ///< input clear integrator, set accumulator to 0
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        input   wire    signed [INP_DW-1:0]     inp_samp_data,  ///< input data
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        input                                                           inp_samp_str,   ///< input data ready strobe
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        output  wire    signed [OUT_DW-1:0]     out_samp_data,  ///< output data
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        output                                                          out_samp_str    ///< output data ready strobe
20 7 Juzujka 
);
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/*********************************************************************************************/
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`include "cic_functions.vh"
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/*********************************************************************************************/
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localparam      B_max = clog2_l((CIC_R * CIC_M) ** CIC_N) + INP_DW - 1;
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/*********************************************************************************************/
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genvar  i;
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generate
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        for (i = 0; i < CIC_N; i = i + 1) begin : int_stage
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                localparam B_jm1        = B_calc(i    , CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);   ///< the number of bits to prune in previous stage
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                localparam B_j          = B_calc(i + 1, CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);   ///< the number of bits to prune in current stage
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                localparam idw_cur = B_max - B_jm1 + 1;         ///< data width on the input
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                localparam odw_cur = B_max - B_j   + 1;         ///< data width on the output
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                wire signed [idw_cur - 1 : 0] int_in;           ///< input data bus
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                if ( i == 0 )   assign int_in = inp_samp_data;                          ///< if it is the first stage, then takes data from input of CIC filter
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                        else            assign int_in = int_stage[i - 1].int_out;       ///< otherwise, takes data from the previous stage of the filter
36 7 Juzujka 
                wire signed [odw_cur - 1 : 0] int_out;
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                integrator #(
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                                idw_cur,
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                                odw_cur
40 7 Juzujka 
                                )
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                        int_inst(
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                                .clk                    (clk),
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                                .reset_n                (reset_n),
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                                .clear                  (clear) ,
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                                .inp_samp_data  (int_in),
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                                .inp_samp_str   (inp_samp_str),
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                                .out_samp_data  (int_out)
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                                );
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                initial begin
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                        //$display("i:%d integ idw=%2d odw=%2d  B(%2d, %3d, %2d, %2d, %2d, %2d)=%2d, Bj-1=%2d, F_sq=%8d", i, idw_cur, odw_cur, i + 1, CIC_R, CIC_M, CIC_N, INP_DW, OUT_DW, B_j, B_jm1, F_sq_j);
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                        $display("i:%d integ idw=%d ", i, idw_cur);
52 
                end
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        end
54 
endgenerate
55 
/*********************************************************************************************/
56 9 Juzujka 
/// downsampler takes data from m-th stage
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localparam B_m = B_calc(CIC_N, CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);    ///< bits to prune on the m-th stage
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localparam ds_dw = B_max - B_m + 1;                                                                             ///< data width of the downsampler
59 7 Juzujka 
wire    signed [ds_dw - 1 : 0]  ds_out_samp_data;
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wire                                                    ds_out_samp_str;
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/*********************************************************************************************/
62 
initial begin
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        //$display("i downsamp dw %d , int_stage[%2d].dw_out = %2d", ds_dw, CIC_N - 1, int_stage[CIC_N - 1].odw_cur);
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        $display("i downsamp dw %d", ds_dw);
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end
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downsampler #(
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                .DATA_WIDTH_INP (ds_dw),
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                .CIC_R                  (CIC_R)
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        )
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        downsampler_inst
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        (
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                .clk                    (clk),
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                .reset_n                (reset_n),
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                .clear                  (clear),
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                .inp_samp_data  (int_stage[CIC_N - 1].int_out),
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                .inp_samp_str   (inp_samp_str),
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                .out_samp_data  (ds_out_samp_data),
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                .out_samp_str   (ds_out_samp_str)
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        );
80 
/*********************************************************************************************/
81 
genvar  j;
82 
wire comb_chain_out_str;
83 
reg     [CIC_N : 0]     comb_inp_str_d;
84 
generate
85 
        wire summ_rdy_str;
86 9 Juzujka 
        if (SMALL_FOOTPRINT != 0) begin ///< generate comb for small footprint
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                always @(negedge reset_n or posedge clk)        ///< shift register for strobe from datasampler, used to latch data from comb at N'th clock after downsamplers strobe
88 7 Juzujka 
                        if              (~reset_n)      comb_inp_str_d <= '0;
89 
                        else if (clear)         comb_inp_str_d <= '0;
90 
                        else                            comb_inp_str_d <= {comb_inp_str_d[CIC_N - 1 : 0], ds_out_samp_str};
91 
        end
92 
 
93 
        if (SMALL_FOOTPRINT == 0)       assign summ_rdy_str = '0;
94 
        else                                            assign summ_rdy_str = comb_inp_str_d[CIC_N];
95 
 
96 
 
97 
        for (j = 0; j < CIC_N; j = j + 1) begin : comb_stage
98 
                localparam B_m_j_m1             =    B_calc(CIC_N + j    ,      CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);
99 
                localparam B_m_j                =    B_calc(CIC_N + j + 1,      CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);
100 
                localparam idw_cur = B_max - B_m_j_m1 + 1;
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                localparam odw_cur = B_max - B_m_j + 1;
102 
                wire signed [idw_cur - 1 : 0] comb_in;
103 
                wire signed [idw_cur - 1 : 0] comb_inst_out;
104 
                wire signed [odw_cur - 1 : 0] comb_out;
105 
                wire comb_dv;
106 
                if (j == 0)     assign comb_in = ds_out_samp_data;
107 
                        else    assign comb_in = comb_stage[j - 1].comb_out;
108 
                assign comb_out = comb_inst_out[idw_cur - 1 -: odw_cur];
109 
                comb #(
110 
                                .SAMP_WIDTH             (idw_cur),
111 
                                .CIC_M                  (CIC_M),
112 
                                .SMALL_FOOTPRINT(SMALL_FOOTPRINT)
113 
                        )
114 
                        comb_inst(
115 
                                .clk                    (clk),
116 
                                .reset_n                (reset_n),
117 
                                .clear                  (clear),
118 
                                .samp_inp_str   (ds_out_samp_str),
119 
                                .samp_inp_data  (comb_in),
120 
                                .summ_rdy_str   (summ_rdy_str),
121 
                                .samp_out_str   (comb_dv),
122 
                                .samp_out_data  (comb_inst_out)
123 
                                );
124 
                if (SMALL_FOOTPRINT == 0)       assign comb_chain_out_str = comb_stage[CIC_N - 1].comb_dv;
125 
                else                                            assign comb_chain_out_str = comb_inp_str_d[CIC_N - 1];
126 
                initial begin
127 9 Juzujka 
                        //$display("i:%d  comb idw=%2d odw=%2d  B(%2d, %3d, %2d, %2d, %2d, %2d)=%2d", j, idw_cur, odw_cur, CIC_N + j + 1, CIC_R, CIC_M, CIC_N, INP_DW, OUT_DW, B_m_j);
128 7 Juzujka 
                        //if (j != 0) $display("odw_prev=%2d, comb_stage[j - 1].odw_cur=%2d", odw_prev, comb_stage[j - 1].odw_cur);
129 
                        $display("i:%d  comb idw=%d", j, idw_cur);
130 
                end
131 
        end
132 
endgenerate
133 
/*********************************************************************************************/
134 
localparam dw_out = B_max - B_calc(2 * CIC_N, CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW) + 1;
135 
reg             signed [OUT_DW-1:0]     comb_out_samp_data_reg;
136 
reg                                                     comb_out_samp_str_reg;
137 
 
138 
always @(negedge reset_n or posedge clk)
139 
begin
140 
        if              (~reset_n)                                      comb_out_samp_data_reg <= '0;
141 
        else if (comb_chain_out_str)            comb_out_samp_data_reg <= comb_stage[CIC_N - 1].comb_out[dw_out - 1 -: OUT_DW];
142 
end
143 
 
144 
always @(negedge reset_n or posedge clk)
145 
        if              (~reset_n)                                      comb_out_samp_str_reg <= '0;
146 
        else if (clear)                                         comb_out_samp_str_reg <= '0;
147 
        else                                                            comb_out_samp_str_reg <= comb_chain_out_str;
148 
 
149 
assign out_samp_data    = comb_out_samp_data_reg;
150 
assign out_samp_str             = comb_out_samp_str_reg;
151 
/*********************************************************************************************/
152 
task print_parameters_nice;
153 
        integer tot_registers;
154 
        integer j;
155 
        integer B_2Np1;
156 
        integer dw_j;
157 
        integer B_j;
158 
        reg [127:0] h_f0_pre;
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        integer log2_h_f0_pre;
160 
        integer h_f0_pre_limit_prec;
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        integer h_f0_pre_divider;
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        integer h_f0_divider_exp;
163 
        integer h_f0_x_mul;
164 
        integer x_multiplier;
165 
        reg [127:0] F_sq_curr;
166 
        x_multiplier = 100000;
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        B_2Np1 = B_max - dw_out + 1;
168 
        h_f0_pre = (CIC_R*CIC_M)**CIC_N;
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        h_f0_divider_exp = (B_2Np1 + 1);
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        h_f0_pre_limit_prec = 30;
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        log2_h_f0_pre = clog2_l(h_f0_pre);
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        if (log2_h_f0_pre > h_f0_pre_limit_prec) begin
173 
                //$display(" log2_h_f0_pre = %2d, lim %2d", log2_h_f0_pre, h_f0_pre_limit_prec);
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                h_f0_pre_divider = log2_h_f0_pre - h_f0_pre_limit_prec;
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                //$display(" h_f0_pre_divider = %2d", h_f0_pre_divider);
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                h_f0_pre = h_f0_pre >> h_f0_pre_divider;
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                h_f0_divider_exp = h_f0_divider_exp - h_f0_pre_divider;
178 
                //$display(" log2_h_f0_pre limited = %2d, divider_exp limited %2d", log2_h_f0_pre, h_f0_divider_exp);
179 
                h_f0_x_mul = x_multiplier * h_f0_pre / 2**(h_f0_divider_exp);
180 
        end
181 
        else begin
182 
                h_f0_x_mul = x_multiplier * h_f0_pre / 2**(B_2Np1 + 1);
183 
        end
184 
        $display("CIC inp_dw   %d", INP_DW);
185 
        $display("CIC out_dw   %d", OUT_DW);
186 
        $display("CIC B_max    %d", B_max);
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        $display("CIC B_out    %d", dw_out);
188 
        $display("CIC B_2Np1   %d", B_2Np1);
189 
        $display("CIC h(f=0)   %1d.%1d", h_f0_x_mul / x_multiplier, h_f0_x_mul % x_multiplier);
190 
        $display(" clog2_l((r*m)**n)  %d", clog2_l((CIC_R*CIC_M)**CIC_N));
191 
        tot_registers = 0;
192 
        for (j = 1; j < 2 * CIC_N + 2; j = j + 1) begin : check_Bj
193 
                F_sq_curr = F_sq_calc(j, CIC_N, CIC_R, CIC_M);
194 
                B_j = B_calc(j, CIC_N, CIC_R, CIC_M, INP_DW, OUT_DW);
195 
                dw_j = B_max - B_j + 1;
196 
                tot_registers = tot_registers + dw_j;
197 
        end
198 
        $display("CIC total registers %2d", tot_registers);
199 
endtask
200 
 
201 
 
202 
generate
203 
        initial begin : initial_print_parameters
204 
        if (1) begin
205 
                print_parameters_nice;
206 
        end
207 
 
208 
        end
209 
        if (0) begin
210 
                for (j = 0; j < CIC_N; j = j + 1) begin : print_int_stage
211 
                        initial begin
212 
                                $display("CIC integrator j:%2d B %2d B_ jm1 %2d odw_prev %2d in_dw %3d out_dw %3d data_width_pass %3d", j + 1, int_stage[j].B_j, int_stage[j].B_jm1, int_stage[j].odw_prev, int_stage[j].idw_cur, int_stage[j].odw_cur, 0);
213 
                        end
214 
                end
215 
                initial begin
216 
                                $display("CIC downsampler     B %2d                                  ds_dw %3d", B_m, ds_dw);
217 
                end
218 
                for (j = 0; j < CIC_N; j = j + 1) begin : print_comb_stage
219 
                        initial begin
220 
                                $display("CIC comb       j:%2d B %2d B_mjm1 %2d             in_dw %3d out_dw %3d", j, comb_stage[j].B_m_j, comb_stage[j].B_m_j_m1, comb_stage[j].idw_cur, comb_stage[j].odw_cur);
221 
                        end
222 
                end
223 
                initial begin
224 
                        $display("CIC out odw %3d", OUT_DW);
225 
                end
226 
        end
227 
endgenerate
228 
endmodule

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