Improve_synthesizer_sound

Improve synthesizer sound

Arcade-DonkeyKong.sv

@@ -194,7 +194,7 @@ wire [1:0] ar = status[20:19];
 assign VIDEO_ARX = (!ar) ? ((status[2]|mod_pestplace)  ? 8'd8 : 8'd7) : (ar - 1'd1);
 assign VIDEO_ARY = (!ar) ? ((status[2]|mod_pestplace)  ? 8'd7 : 8'd8) : 12'd0;
 
-`include "build_id.v" 
+`include "build_id.v"
 localparam CONF_STR = {
 	"A.DKONG;;",
 	"H0OJK,Aspect ratio,Original,Full Screen,[ARC1],[ARC2];",
@@ -294,7 +294,7 @@ reg mod_pestplace=0;
 always @(posedge clk_sys) begin
 	reg [7:0] mod = 0;
 	if (ioctl_wr & (ioctl_index==1)) mod <= ioctl_dout;
-	
+
 	mod_dk <= (mod == 0);
 	mod_dkjr <= (mod == 1);
 	mod_dk3 <= (mod == 2);
@@ -371,7 +371,7 @@ arcade_video #(256,12) arcade_video
 wire [15:0] audio;
 assign AUDIO_L = audio;
 assign AUDIO_R = AUDIO_L;
-assign AUDIO_S = 0;
+assign AUDIO_S = 1;
 
 assign hblank = hbl[8];
 
@@ -436,15 +436,15 @@ dpram #(16,8) wav_rom (
 
 
 
-dkong_top dkong(				   
+dkong_top dkong(
 	.I_CLK_24576M(clk_sys),
 	.I_RESETn(~reset),
 	.I_U1(~m_up),
 	.I_D1(~m_down),
 	.I_L1(~m_left),
 	.I_R1(~m_right),
 	.I_J1(~m_fire),
-	
+
 	.I_U2(~m_up_2),
 	.I_D2(~m_down_2),
 	.I_L2(~m_left_2),

files.qip

@@ -12,6 +12,8 @@ set_global_assignment -name VERILOG_FILE rtl/dkong_hv_count.v
 set_global_assignment -name VERILOG_FILE rtl/dkong_col_pal.v
 set_global_assignment -name VERILOG_FILE rtl/dkong_bram.v
 set_global_assignment -name VERILOG_FILE rtl/dkong_adec.v
+set_global_assignment -name SYSTEMVERILOG_FILE rtl/dkongjr_dac.sv
+set_global_assignment -name VERILOG_FILE rtl/dkongjr_iir_filter.v
 set_global_assignment -name VERILOG_FILE rtl/radarscp_stars.v
 set_global_assignment -name QIP_FILE rtl/t48/T48.qip
 set_global_assignment -name QIP_FILE rtl/T80/T80.qip

rtl/dkong_sound.v

@@ -1,22 +1,22 @@
 //===============================================================================
 // FPGA DONKEY KONG SOUND_I/F
 //
-// Version : 4.00 
+// Version : 4.00
 //
 // Copyright(c) 2003 - 2004 Katsumi Degawa , All rights reserved
 //
 // Important !
 //
-// This program is freeware for non-commercial use. 
+// This program is freeware for non-commercial use.
 // An author does no guarantee about this program.
 // You can use this under your own risk.
 //
 // 2004- 9- 2 T48-IP(beta3) was include.  K.Degawa
 // 2004- 9-14 T48-IP was changed to beta4.  K.Degawa
 // 2005- 2- 9 The description of the ROM was changed.
-//            Data on the ROM are initialized at the time of the start.   
+//            Data on the ROM are initialized at the time of the start.
 //================================================================================
- 
+
 module dkong_sound(
 	input   I_CLK,
 	input   I_RST,
@@ -67,7 +67,7 @@ assign  ROM_A = {I_DKJR ? I8035_PBI[3] : I8035_PSENn,S_ROM_A};
 reg     S_D1_CS;
 always@(posedge I_CLK) S_D1_CS <= (I_DKJR | I8035_PBI[6])&(~I8035_RDn);
 
-wire    [7:0]S_D1 = S_D1_CS ? {3'h0,~I_SOUND_DAT[4:0]}: 8'h00 ; 
+wire    [7:0]S_D1 = S_D1_CS ? {3'h0,~I_SOUND_DAT[4:0]}: 8'h00 ;
 
 wire    [7:0]S_PROG_DB;
 wire    [7:0]S_PROG_D  = I8035_PSENn ? 8'h00 : S_PROG_DB ;

rtl/dkong_soundboard.sv

@@ -1,15 +1,17 @@
-module dkong_soundboard(
+module dkong_soundboard #(
+	W_CLK_24576M_RATE = 24576000 // Hz
+) (
 	input         W_CLK_24576M,
 	input         W_RESETn,
-	input         I_DKJR,
+	input         I_DKJR,   /// 1 = Emulate Donkey Kong JR, 3 or PestPlace (async not a problem)
 	input         W_W0_WE,
 	input         W_W1_WE,
 	input         W_CNF_EN,
 	input   [6:0] W_6H_Q,
 	input         W_5H_Q0,
 	input   [1:0] W_4H_Q,
 	input   [4:0] W_3D_Q,
-	output [15:0] O_SOUND_DAT,
+	output reg [15:0] O_SOUND_DAT,
 	output        O_SACK,
 	output [11:0] ROM_A,
 	input   [7:0] ROM_D,
@@ -33,11 +35,17 @@ wire    I8035_T0;
 wire    I8035_T1;
 wire    I8035_RSTn;
 
-reg [1:0] cnt;
+// emulate 6 MHz crystal oscillor
+localparam increment_width = 17; // ceil(RATE_decimal_precision * 3.32192)
+reg [increment_width:0] count; // one longer for overflow bit.
+localparam X1_RATE = 6000000;
+localparam [increment_width:0] increment = (X1_RATE / W_CLK_24576M_RATE) * 2**increment_width;
+
 always @(posedge W_CLK_24576M) begin
-	cnt <= cnt + 1'd1;
-	I8035_CLK_EN <= cnt == 0;
+	count[increment_width] <= 1'b0; // keep overflow bit for just one cycle
+	count <= count + increment;
 end
+assign I8035_CLK_EN = count[increment_width];
 
 I8035IP SOUND_CPU
 (
@@ -73,7 +81,7 @@ dkong_sound Digtal_sound
 	.I8035_DBO(I8035_DBO),
 	.I8035_PAI(I8035_PAI),
 	.I8035_PBI(I8035_PBI),
-	.I8035_PBO(I8035_PBO), 
+	.I8035_PBO(I8035_PBO),
 	.I8035_ALE(I8035_ALE),
 	.I8035_RDn(I8035_RDn),
 	.I8035_PSENn(I8035_PSENn),
@@ -88,30 +96,67 @@ dkong_sound Digtal_sound
 	.ROM_D(ROM_D)
 );
 
-dkong_wav_sound Analog_sound
+//----    DAC  I/F     ------------------------
+
+localparam SAMPLE_RATE = 48000;
+localparam [8:0] clocks_per_sample = 24000000 / 48000;
+
+wire signed[15:0] W_D_S_DATB;
+
+dkongjr_dac dac08
+(
+	.I_CLK(W_CLK_24576M),
+	.I_DECAY_EN(~I8035_PBI[7]),
+	.I_RESET_n(W_RESETn),
+	.I_SND_DAT({2{~W_D_S_DAT[7],W_D_S_DAT[6:0]}}), // convert 8-bit unsigned to 16-bit signed.
+	.O_SND_DAT(W_D_S_DATB)
+);
+
+// Second order low pass filter. f= 1916 Hz, Q = 0.74.
+wire signed[15:0] W_D_S_DATC;
+iir_2nd_order filter
 (
-	.O_ROM_AB(WAV_ROM_A),
-	.I_ROM_DB(WAV_ROM_DO),
+	.clk(W_CLK_24576M),
+	.reset(~W_RESETn),
+	.div({3'd0, clocks_per_sample}),
+	.A2(-18'sd26649),
+	.A3(18'sd11453),
+	.B1(18'sd215),
+	.B2(18'sd430),
+	.B3(18'sd215),
+   .in(W_D_S_DATB),
+	.out(W_D_S_DATC)
+);
 
+// Wav sound recored at 11025 Hz rate, 8 bit unsigned
+dkong_wav_sound #(
+	.CLOCK_RATE(W_CLK_24576M_RATE)
+) Analog_sound (
 	.I_CLK(W_CLK_24576M),
 	.I_RSTn(W_RESETn),
-	.I_SW(I_DKJR ? 2'b00 : W_6H_Q[2:1])
+	.I_SW(I_DKJR ? 2'b00 : W_6H_Q[2:1]),
+	.O_ROM_AB(WAV_ROM_A)
 );
 
 reg[8:0] audio_clk_counter;
-wire audio_clk_en;
-assign audio_clk_en = audio_clk_counter == 0;
-wire signed[15:0] walk_out;
-
+reg audio_clk_en;
 always@(posedge W_CLK_24576M, negedge W_RESETn) begin
 	if(!W_RESETn)begin
+		audio_clk_en <= 0;
 		audio_clk_counter <= 0;
 	end else begin
-		audio_clk_counter <= audio_clk_counter + 1;
+		if(audio_clk_counter != (clocks_per_sample - 9'd1))begin
+			audio_clk_en <= 0;
+			audio_clk_counter <= audio_clk_counter + 9'd1;
+		end else begin
+			audio_clk_en <= 1;
+			audio_clk_counter <= 0;
+		end
 	end
 end
 
-dk_walk #(.CLOCK_RATE(24576000),.SAMPLE_RATE(48000)) walk (
+wire signed[15:0] walk_out;
+dk_walk #(.CLOCK_RATE(W_CLK_24576M_RATE),.SAMPLE_RATE(SAMPLE_RATE)) walk (
 	.clk(W_CLK_24576M),
 	.I_RSTn(W_RESETn),
 	.audio_clk_en(audio_clk_en),
@@ -120,9 +165,16 @@ dk_walk #(.CLOCK_RATE(24576000),.SAMPLE_RATE(48000)) walk (
 );
 
 //  SOUND MIXER (WAV + DIG ) -----------------------
-wire[14:0] sound_mix = ({1'b0, I_DKJR ? 15'd0 : WAV_ROM_DO, 6'b0} + {1'b0, (W_D_S_DAT >> 1) + (W_D_S_DAT >> 3), 6'b0});
-wire signed[15:0] sound_mix_16_bit = sound_mix - 2**14 + walk_out;
 
-assign O_SOUND_DAT = sound_mix_16_bit + 2**15;
+wire signed[15:0] sound_mix =
+	(I_DKJR ? 16'd0 : {{3{~WAV_ROM_DO[7]}}, WAV_ROM_DO[6:0],6'b0}) +
+	{{3{W_D_S_DATC[15]}},W_D_S_DATC[14:2]} + {{5{W_D_S_DATC[15]}},W_D_S_DATC[14:4]} +
+	walk_out;
+
+always@(posedge W_CLK_24576M_RATE) begin
+	if (audio_clk_en) begin
+		O_SOUND_DAT <= sound_mix;
+	end
+end
 
 endmodule

rtl/dkong_top.v

@@ -7,7 +7,7 @@
 //
 // Important !
 //
-// This program is freeware for non-commercial use. 
+// This program is freeware for non-commercial use.
 // An author does no guarantee about this program.
 // You can use this under your own risk.
 //
@@ -26,6 +26,7 @@ module dkong_top
 (
 	//    FPGA_USE
 	input  I_CLK_24576M,
+	input  I_CLK_24M,
 	input  I_RESETn,
 	output O_PIX,
 
@@ -144,7 +145,7 @@ wire   W_CPU_IORQn;
 wire   W_CPU_MREQn;
 wire   W_CPU_BUSRQ;
 wire   W_CPU_BUSAKn;
-wire   W_CPU_RDn;  
+wire   W_CPU_RDn;
 wire   W_CPU_WRn;
 wire   [15:0]W_CPU_A;
 
@@ -153,7 +154,7 @@ assign WB_CLK_12288M = W_CLK_12288M; // 12.288MHz
 wire   W_CPU_CLK_EN_P = W_H_CNT[1:0] == 2'b01;
 wire   W_CPU_CLK_EN_N = W_H_CNT[1:0] == 2'b11;
 
- T80pa z80core(
+T80pa z80core(
 	.RESET_n(W_RESETn),
 	.CLK(I_CLK_24576M),
 	.CEN_p(W_CPU_CLK_EN_N),
@@ -195,7 +196,7 @@ prog ROM(
 
 always @(*) begin
 	case({!I_DKJR, W_CPU_A[15:11]})
-		6'h02: MAIN_CPU_A = {5'h06,W_CPU_A[10:0]}; // 0x1000-0x17FF -> 0x3000-0x37FF in ROM file 
+		6'h02: MAIN_CPU_A = {5'h06,W_CPU_A[10:0]}; // 0x1000-0x17FF -> 0x3000-0x37FF in ROM file
 		6'h03: MAIN_CPU_A = {5'h0B,W_CPU_A[10:0]}; // 0x1800-0x1FFF -> 0x5800-0x5FFF in ROM file
 		6'h05: MAIN_CPU_A = {5'h09,W_CPU_A[10:0]}; // 0x2800-0x2FFF -> 0x4800-0x4FFF in ROM file
 		6'h06: MAIN_CPU_A = {5'h02,W_CPU_A[10:0]}; // 0x3000-0x37FF -> 0x1000-0x17FF in ROM file
@@ -370,7 +371,7 @@ dkong_adec adec
 	.I_DK3B(I_DK3B),
 	.I_PESTPLCE(I_PESTPLCE),
 	.I_AB(W_CPU_A),
-	.I_DB(WI_D), 
+	.I_DB(WI_D),
 	.I_MREQ_n(W_CPU_MREQn),
 	.I_RFSH_n(W_CPU_RFSHn),
 	.I_RD_n(W_CPU_RDn),
@@ -497,7 +498,7 @@ dkong_vram vram
 	.DL_ADDR(DL_ADDR),
 	.DL_WR(DL_WR),
 	.DL_DATA(DL_DATA),
-	
+
 	.hs_address(hs_address),
 	.hs_data_in(hs_data_in),
 	.hs_data_out(hs_data_out_VRAM),
@@ -579,5 +580,5 @@ dkong_soundboard dkong_soundboard(
 	.WAV_ROM_A(WAV_ROM_A),
 	.WAV_ROM_DO(WAV_ROM_DO)
 	);
-	
+
 endmodule