書き込みには，MAX10-JBを利用した．USB Blaster互換のJTAGモジュールとして使える．
特別版No.3のMAX10基板を，Pmodポートを拡張するベースボードに接続した．
音を出すモジュールとして，PMOD-AUDIO V1.2（muse lab）を使用した．信号1本で制御できる．
単純な矩形波で音を鳴らすデザインをベースに，いい感じに音色を変えるように指示した．
●Claudeの回答
単純な矩形波駆動からウェーブテーブル音源方式に作り直しました。
変更点
波形ROM — 1〜8倍音を減衰させながら合成した256サンプルの単周期波形（打弦楽器的なスペクトルの近似）をcase文ベースのROMとして実装
DDS位相アキュムレータ — 16bit、約48kHz（AUDIO_DIV=1042）のサンプルレートで波形ROMを読み出し
アタック/ディケイ・エンベロープ — 発音開始で約0.7msの高速アタック→フルスケール到達後は約0.8ms毎にenv -= env >> 6の指数減衰。ピアノやハンマー打弦楽器特有の「叩いた瞬間が最大音量、あとは自然に減衰していく」性質を再現しています
8bit PWM DAC — 波形サンプル×エンベロープの積をPWMデューティに変換し、CLK/256（約195kHz）のキャリアで出力（PMOD-AUDIO側のRCフィルタでさらに平滑化されます）
●生成された音源部分（およびシーケンサ）
// 省略
module jingle_player #(
parameter int CLK_HZ = 50_000_000,
parameter int AUDIO_DIV = 1042 // audio sample tick every AUDIO_DIV clk cycles (~48kHz)
) (
input logic clk,
input logic rst,
output logic audio
);
// 省略
localparam int NUM_STEPS = 6;
localparam logic [2:0] REST_STEP = 3'd5;
logic [2:0] step;
logic [2:0] next_step;
logic [15:0] phase_inc;
logic [26:0] duration_cyc;
assign next_step = (step == NUM_STEPS - 1) ? 3'd0 : step + 3'd1;
always_comb begin
unique case (step)
3'd0: begin phase_inc = 16'd505; duration_cyc = 27'd10_000_000; end // F#4, 200ms
3'd1: begin phase_inc = 16'd379; duration_cyc = 27'd10_000_000; end // C#4, 200ms
3'd2: begin phase_inc = 16'd505; duration_cyc = 27'd10_000_000; end // F#4, 200ms
3'd3: begin phase_inc = 16'd379; duration_cyc = 27'd10_000_000; end // C#4, 200ms
3'd4: begin phase_inc = 16'd567; duration_cyc = 27'd30_000_000; end // G#4, 600ms
default: begin phase_inc = 16'd567; duration_cyc = 27'd130_000_000; end // ring-out, 2.6s
endcase
end
// -----------------------
// Step/duration sequencer
// -----------------------
logic [26:0] dur_cnt;
logic step_done;
logic note_on_pulse; // fires only when the *upcoming* step is a real note
assign step_done = (dur_cnt == duration_cyc - 27'd1);
assign note_on_pulse = step_done && (next_step != REST_STEP);
always_ff @(posedge clk) begin
if (rst) begin
dur_cnt <= '0;
step <= '0;
end else if (step_done) begin
dur_cnt <= '0;
step <= next_step;
end else begin
dur_cnt <= dur_cnt + 27'd1;
end
end
// ------------------------------------------
// Audio sample-rate tick (~48kHz strobe, free running)
// ------------------------------------------
logic [10:0] smp_cnt;
logic smp_en;
assign smp_en = (smp_cnt == AUDIO_DIV - 1);
always_ff @(posedge clk) begin
if (rst) smp_cnt <= '0;
else if (smp_en) smp_cnt <= '0;
else smp_cnt <= smp_cnt + 11'd1;
end
// 省略
logic [15:0] phase;
always_ff @(posedge clk) begin
if (rst) begin
phase <= '0;
end else if (note_on_pulse) begin
phase <= '0;
end else if (smp_en) begin
phase <= phase + phase_inc;
end
end
// ---------------------------------------------------------------
// Attack/decay envelope. Fast linear attack, then a slow "leaky"
// exponential decay (~2.5s time constant) for a long bell-like ring.
// Only retriggers (fresh attack) on a real note-on; during the rest
// step it simply continues decaying from wherever it left off.
// ---------------------------------------------------------------
localparam logic ENV_ATTACK = 1'b0;
localparam logic ENV_DECAY = 1'b1;
localparam logic [7:0] ATTACK_STEP = 8'd8; // envelope units added per sample (~0.7ms to full scale)
localparam int DECAY_TICK = 48; // samples between each decay update (~1ms @48kHz)
localparam int DECAY_SHIFT = 9; // decay rate: env -= env >> DECAY_SHIFT (~2.5s to silence)
logic env_state;
logic [7:0] env;
logic [5:0] decay_cnt;
always_ff @(posedge clk) begin
if (rst) begin
env <= 8'd0;
env_state <= ENV_ATTACK;
decay_cnt <= '0;
end else if (note_on_pulse) begin
env <= 8'd0;
env_state <= ENV_ATTACK;
decay_cnt <= '0;
end else if (smp_en) begin
if (env_state == ENV_ATTACK) begin
if (env >= 8'd255 - ATTACK_STEP) begin
env <= 8'd255;
env_state <= ENV_DECAY;
end else begin
env <= env + ATTACK_STEP;
end
end else begin // ENV_DECAY
if (decay_cnt == DECAY_TICK - 1) begin
decay_cnt <= '0;
env <= env - (env >> DECAY_SHIFT);
end else begin
decay_cnt <= decay_cnt + 6'd1;
end
end
end
end
// --------------------------------------------------
// Bell/chime-like single-cycle waveform ROM (256 entries, signed
// --------------------------------------------------
function automatic logic signed [7:0] wave_rom(input logic [7:0] idx);
case (idx)
8'd0: wave_rom = 8'sd0;
8'd1: wave_rom = 8'sd20;
8'd2: wave_rom = 8'sd40;
8'd3: wave_rom = 8'sd58;
8'd4: wave_rom = 8'sd75;
8'd5: wave_rom = 8'sd90;
8'd6: wave_rom = 8'sd103;
8'd7: wave_rom = 8'sd113;
8'd8: wave_rom = 8'sd120;
8'd9: wave_rom = 8'sd125;
8'd10: wave_rom = 8'sd127;
8'd11: wave_rom = 8'sd127;
8'd12: wave_rom = 8'sd125;
8'd13: wave_rom = 8'sd122;
8'd14: wave_rom = 8'sd118;
8'd15: wave_rom = 8'sd113;
8'd16: wave_rom = 8'sd108;
8'd17: wave_rom = 8'sd103;
8'd18: wave_rom = 8'sd98;
8'd19: wave_rom = 8'sd95;
8'd20: wave_rom = 8'sd92;
8'd21: wave_rom = 8'sd90;
8'd22: wave_rom = 8'sd89;
8'd23: wave_rom = 8'sd89;
8'd24: wave_rom = 8'sd89;
8'd25: wave_rom = 8'sd90;
8'd26: wave_rom = 8'sd92;
8'd27: wave_rom = 8'sd94;
8'd28: wave_rom = 8'sd95;
8'd29: wave_rom = 8'sd97;
8'd30: wave_rom = 8'sd98;
8'd31: wave_rom = 8'sd99;
8'd32: wave_rom = 8'sd99;
8'd33: wave_rom = 8'sd99;
8'd34: wave_rom = 8'sd99;
8'd35: wave_rom = 8'sd99;
8'd36: wave_rom = 8'sd98;
8'd37: wave_rom = 8'sd98;
8'd38: wave_rom = 8'sd98;
8'd39: wave_rom = 8'sd98;
8'd40: wave_rom = 8'sd98;
8'd41: wave_rom = 8'sd99;
8'd42: wave_rom = 8'sd100;
8'd43: wave_rom = 8'sd102;
8'd44: wave_rom = 8'sd104;
8'd45: wave_rom = 8'sd107;
8'd46: wave_rom = 8'sd109;
8'd47: wave_rom = 8'sd112;
8'd48: wave_rom = 8'sd114;
8'd49: wave_rom = 8'sd116;
8'd50: wave_rom = 8'sd118;
8'd51: wave_rom = 8'sd119;
8'd52: wave_rom = 8'sd119;
8'd53: wave_rom = 8'sd119;
8'd54: wave_rom = 8'sd118;
8'd55: wave_rom = 8'sd116;
8'd56: wave_rom = 8'sd114;
8'd57: wave_rom = 8'sd111;
8'd58: wave_rom = 8'sd108;
8'd59: wave_rom = 8'sd104;
8'd60: wave_rom = 8'sd101;
8'd61: wave_rom = 8'sd97;
8'd62: wave_rom = 8'sd94;
8'd63: wave_rom = 8'sd90;
8'd64: wave_rom = 8'sd87;
8'd65: wave_rom = 8'sd85;
8'd66: wave_rom = 8'sd82;
8'd67: wave_rom = 8'sd79;
8'd68: wave_rom = 8'sd77;
8'd69: wave_rom = 8'sd74;
8'd70: wave_rom = 8'sd72;
8'd71: wave_rom = 8'sd69;
8'd72: wave_rom = 8'sd66;
8'd73: wave_rom = 8'sd62;
8'd74: wave_rom = 8'sd58;
8'd75: wave_rom = 8'sd54;
8'd76: wave_rom = 8'sd49;
8'd77: wave_rom = 8'sd43;
8'd78: wave_rom = 8'sd38;
8'd79: wave_rom = 8'sd32;
8'd80: wave_rom = 8'sd27;
8'd81: wave_rom = 8'sd21;
8'd82: wave_rom = 8'sd16;
8'd83: wave_rom = 8'sd11;
8'd84: wave_rom = 8'sd6;
8'd85: wave_rom = 8'sd2;
8'd86: wave_rom = -8'sd2;
8'd87: wave_rom = -8'sd5;
8'd88: wave_rom = -8'sd7;
8'd89: wave_rom = -8'sd9;
8'd90: wave_rom = -8'sd11;
8'd91: wave_rom = -8'sd12;
8'd92: wave_rom = -8'sd13;
8'd93: wave_rom = -8'sd14;
8'd94: wave_rom = -8'sd15;
8'd95: wave_rom = -8'sd16;
8'd96: wave_rom = -8'sd17;
8'd97: wave_rom = -8'sd18;
8'd98: wave_rom = -8'sd19;
8'd99: wave_rom = -8'sd20;
8'd100: wave_rom = -8'sd21;
8'd101: wave_rom = -8'sd22;
8'd102: wave_rom = -8'sd22;
8'd103: wave_rom = -8'sd22;
8'd104: wave_rom = -8'sd21;
8'd105: wave_rom = -8'sd19;
8'd106: wave_rom = -8'sd17;
8'd107: wave_rom = -8'sd13;
8'd108: wave_rom = -8'sd8;
8'd109: wave_rom = -8'sd3;
8'd110: wave_rom = 8'sd3;
8'd111: wave_rom = 8'sd10;
8'd112: wave_rom = 8'sd17;
8'd113: wave_rom = 8'sd24;
8'd114: wave_rom = 8'sd31;
8'd115: wave_rom = 8'sd38;
8'd116: wave_rom = 8'sd44;
8'd117: wave_rom = 8'sd49;
8'd118: wave_rom = 8'sd52;
8'd119: wave_rom = 8'sd54;
8'd120: wave_rom = 8'sd54;
8'd121: wave_rom = 8'sd52;
8'd122: wave_rom = 8'sd49;
8'd123: wave_rom = 8'sd44;
8'd124: wave_rom = 8'sd37;
8'd125: wave_rom = 8'sd29;
8'd126: wave_rom = 8'sd20;
8'd127: wave_rom = 8'sd10;
8'd128: wave_rom = 8'sd0;
8'd129: wave_rom = -8'sd10;
8'd130: wave_rom = -8'sd20;
8'd131: wave_rom = -8'sd29;
8'd132: wave_rom = -8'sd37;
8'd133: wave_rom = -8'sd44;
8'd134: wave_rom = -8'sd49;
8'd135: wave_rom = -8'sd52;
8'd136: wave_rom = -8'sd54;
8'd137: wave_rom = -8'sd54;
8'd138: wave_rom = -8'sd52;
8'd139: wave_rom = -8'sd49;
8'd140: wave_rom = -8'sd44;
8'd141: wave_rom = -8'sd38;
8'd142: wave_rom = -8'sd31;
8'd143: wave_rom = -8'sd24;
8'd144: wave_rom = -8'sd17;
8'd145: wave_rom = -8'sd10;
8'd146: wave_rom = -8'sd3;
8'd147: wave_rom = 8'sd3;
8'd148: wave_rom = 8'sd8;
8'd149: wave_rom = 8'sd13;
8'd150: wave_rom = 8'sd17;
8'd151: wave_rom = 8'sd19;
8'd152: wave_rom = 8'sd21;
8'd153: wave_rom = 8'sd22;
8'd154: wave_rom = 8'sd22;
8'd155: wave_rom = 8'sd22;
8'd156: wave_rom = 8'sd21;
8'd157: wave_rom = 8'sd20;
8'd158: wave_rom = 8'sd19;
8'd159: wave_rom = 8'sd18;
8'd160: wave_rom = 8'sd17;
8'd161: wave_rom = 8'sd16;
8'd162: wave_rom = 8'sd15;
8'd163: wave_rom = 8'sd14;
8'd164: wave_rom = 8'sd13;
8'd165: wave_rom = 8'sd12;
8'd166: wave_rom = 8'sd11;
8'd167: wave_rom = 8'sd9;
8'd168: wave_rom = 8'sd7;
8'd169: wave_rom = 8'sd5;
8'd170: wave_rom = 8'sd2;
8'd171: wave_rom = -8'sd2;
8'd172: wave_rom = -8'sd6;
8'd173: wave_rom = -8'sd11;
8'd174: wave_rom = -8'sd16;
8'd175: wave_rom = -8'sd21;
8'd176: wave_rom = -8'sd27;
8'd177: wave_rom = -8'sd32;
8'd178: wave_rom = -8'sd38;
8'd179: wave_rom = -8'sd43;
8'd180: wave_rom = -8'sd49;
8'd181: wave_rom = -8'sd54;
8'd182: wave_rom = -8'sd58;
8'd183: wave_rom = -8'sd62;
8'd184: wave_rom = -8'sd66;
8'd185: wave_rom = -8'sd69;
8'd186: wave_rom = -8'sd72;
8'd187: wave_rom = -8'sd74;
8'd188: wave_rom = -8'sd77;
8'd189: wave_rom = -8'sd79;
8'd190: wave_rom = -8'sd82;
8'd191: wave_rom = -8'sd85;
8'd192: wave_rom = -8'sd87;
8'd193: wave_rom = -8'sd90;
8'd194: wave_rom = -8'sd94;
8'd195: wave_rom = -8'sd97;
8'd196: wave_rom = -8'sd101;
8'd197: wave_rom = -8'sd104;
8'd198: wave_rom = -8'sd108;
8'd199: wave_rom = -8'sd111;
8'd200: wave_rom = -8'sd114;
8'd201: wave_rom = -8'sd116;
8'd202: wave_rom = -8'sd118;
8'd203: wave_rom = -8'sd119;
8'd204: wave_rom = -8'sd119;
8'd205: wave_rom = -8'sd119;
8'd206: wave_rom = -8'sd118;
8'd207: wave_rom = -8'sd116;
8'd208: wave_rom = -8'sd114;
8'd209: wave_rom = -8'sd112;
8'd210: wave_rom = -8'sd109;
8'd211: wave_rom = -8'sd107;
8'd212: wave_rom = -8'sd104;
8'd213: wave_rom = -8'sd102;
8'd214: wave_rom = -8'sd100;
8'd215: wave_rom = -8'sd99;
8'd216: wave_rom = -8'sd98;
8'd217: wave_rom = -8'sd98;
8'd218: wave_rom = -8'sd98;
8'd219: wave_rom = -8'sd98;
8'd220: wave_rom = -8'sd98;
8'd221: wave_rom = -8'sd99;
8'd222: wave_rom = -8'sd99;
8'd223: wave_rom = -8'sd99;
8'd224: wave_rom = -8'sd99;
8'd225: wave_rom = -8'sd99;
8'd226: wave_rom = -8'sd98;
8'd227: wave_rom = -8'sd97;
8'd228: wave_rom = -8'sd95;
8'd229: wave_rom = -8'sd94;
8'd230: wave_rom = -8'sd92;
8'd231: wave_rom = -8'sd90;
8'd232: wave_rom = -8'sd89;
8'd233: wave_rom = -8'sd89;
8'd234: wave_rom = -8'sd89;
8'd235: wave_rom = -8'sd90;
8'd236: wave_rom = -8'sd92;
8'd237: wave_rom = -8'sd95;
8'd238: wave_rom = -8'sd98;
8'd239: wave_rom = -8'sd103;
8'd240: wave_rom = -8'sd108;
8'd241: wave_rom = -8'sd113;
8'd242: wave_rom = -8'sd118;
8'd243: wave_rom = -8'sd122;
8'd244: wave_rom = -8'sd125;
8'd245: wave_rom = -8'sd127;
8'd246: wave_rom = -8'sd127;
8'd247: wave_rom = -8'sd125;
8'd248: wave_rom = -8'sd120;
8'd249: wave_rom = -8'sd113;
8'd250: wave_rom = -8'sd103;
8'd251: wave_rom = -8'sd90;
8'd252: wave_rom = -8'sd75;
8'd253: wave_rom = -8'sd58;
8'd254: wave_rom = -8'sd40;
8'd255: wave_rom = -8'sd20;
endcase
endfunction
logic signed [7:0] wave_sample;
assign wave_sample = wave_rom(phase[15:8]);
// ---------------------------------------------------------------
// wave_sample (signed) x env (unsigned volume) -> dry sample, then
// through the reverb (3 comb filters + 1 allpass, BRAM delay lines)
// ---------------------------------------------------------------
logic signed [16:0] product;
logic signed [13:0] dry_sample;
assign product = wave_sample * $signed({1'b0, env});
assign dry_sample = product >>> 2;
logic rvb_en;
logic signed [13:0] rvb_out;
logic signed [13:0] rvb_hold;
reverb #(.DATA_W(14)) u_reverb (
.clk (clk),
.rst (rst),
.smp_en (smp_en),
.dry_sample (dry_sample),
.out_en (rvb_en),
.out_sample (rvb_out)
);
// Hold the latest reverb output steady between audio ticks -- the
// reverb's internal pipeline (a few clk cycles) is far shorter than
// the ~1000+ clk audio sample period, so this never sees stale data.
always_ff @(posedge clk) begin
if (rst) rvb_hold <= '0;
else if (rvb_en) rvb_hold <= rvb_out;
end
logic signed [9:0] duty_sum;
logic [7:0] pwm_duty;
assign duty_sum = 10'sd128 + (rvb_hold >>> 6);
always_comb begin
if (duty_sum < 10'sd0) pwm_duty = 8'd0;
else if (duty_sum > 10'sd255) pwm_duty = 8'd255;
else pwm_duty = duty_sum[7:0];
end
// ------------------------------------------------
// 8-bit PWM DAC, free-running at CLK_HZ/256 (~195kHz carrier)
// ------------------------------------------------
logic [7:0] pwm_cnt;
always_ff @(posedge clk) begin
if (rst) pwm_cnt <= '0;
else pwm_cnt <= pwm_cnt + 8'd1;
end
assign audio = (pwm_cnt < pwm_duty);
endmodule広げる