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zx-sizif-xxs/fpga/rtl/turbosound.sv
2021-06-14 11:49:27 +03:00

101 lines
2.2 KiB
Systemverilog

module turbosound(
input rst_n,
input clk28,
input ck35,
input en,
cpu_bus bus,
output [7:0] d_out,
output d_out_active,
input pause,
output [7:0] ay_a0,
output [7:0] ay_b0,
output [7:0] ay_c0,
output [7:0] ay_a1,
output [7:0] ay_b1,
output [7:0] ay_c1
);
reg ay_bdir;
reg ay_bc1;
reg ay_sel;
wire ay_rd0 = bus.rd && ay_bc1 == 1'b1 && ay_bdir == 1'b0 && ay_sel == 1'b0;
wire ay_rd1 = bus.rd && ay_bc1 == 1'b1 && ay_bdir == 1'b0 && ay_sel == 1'b1;
wire port_bffd = bus.ioreq && bus.a_reg[15] == 1'b1 && bus.a_reg[1] == 0;
wire port_fffd = bus.ioreq && bus.a_reg[15] == 1'b1 && bus.a_reg[14] == 1'b1 && bus.a_reg[1] == 0;
always @(posedge clk28 or negedge rst_n) begin
if (!rst_n) begin
ay_bc1 <= 0;
ay_bdir <= 0;
ay_sel <= 0;
end
else begin
ay_bc1 <= en && port_fffd;
ay_bdir <= en && port_bffd && bus.wr;
if (bus.ioreq && port_fffd && bus.wr && bus.d_reg[7:3] == 5'b11111)
ay_sel <= bus.d_reg[0];
end
end
reg [1:0] ay_ck;
always @(posedge clk28 or negedge rst_n) begin
if (!rst_n)
ay_ck <= 0;
else if (ck35 && en && !pause)
ay_ck <= ay_ck + 1'b1;
else
ay_ck[1] <= 0;
end
wire [7:0] ay_dout0, ay_dout1;
YM2149 ym2149_0(
.CLK(clk28),
.ENA(ay_ck[1]),
.RESET_H(~rst_n),
.I_SEL_L(1'b1),
.I_DA(bus.d_reg),
.O_DA(ay_dout0),
.I_REG(1'b0),
.busctrl_addr(ay_bc1 & ay_bdir & ~ay_sel),
.busctrl_we(~ay_bc1 & ay_bdir & ~ay_sel),
.ctrl_aymode(1'b1),
.port_a_i(8'hff),
.port_b_i(8'hff),
.port_a_o(),
.port_b_o(),
.O_AUDIO_A(ay_a0),
.O_AUDIO_B(ay_b0),
.O_AUDIO_C(ay_c0)
);
YM2149 ym2149_1(
.CLK(clk28),
.ENA(ay_ck[1]),
.RESET_H(~rst_n),
.I_SEL_L(1'b1),
.I_DA(bus.d_reg),
.O_DA(ay_dout1),
.I_REG(1'b0),
.busctrl_addr(ay_bc1 & ay_bdir & ay_sel),
.busctrl_we(~ay_bc1 & ay_bdir & ay_sel),
.ctrl_aymode(1'b1),
.port_a_i(8'hff),
.port_b_i(8'hff),
.port_a_o(),
.port_b_o(),
.O_AUDIO_A(ay_a1),
.O_AUDIO_B(ay_b1),
.O_AUDIO_C(ay_c1)
);
assign d_out_active = ay_rd0 | ay_rd1;
assign d_out = ay_rd1? ay_dout1 : ay_dout0;
endmodule