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Code Issues Releases Wiki Activity

[C64] SID: read back the last written value

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This commit is contained in:
Gyorgy Szombathelyi
2019-01-31 18:54:17 +01:00
parent 142cba49bb
commit 0f1eb43301
2 changed files with 6 additions and 14 deletions
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16
cores/c64/rtl/sid/sid_regs.vhd
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@@ -98,6 +98,7 @@ architecture gideon of sid_regs is
signal sust_rel : byte_array_t(0 to 15) := (others => (others => '0'));
signal do_write : std_logic;
signal wdata_d : std_logic_vector(7 downto 0);
signal last_write : std_logic_vector(7 downto 0);
signal filt_en_i: std_logic_vector(15 downto 0) := (others => '0');
constant address_remap : byte_array_t(0 to 255) := (
@@ -159,6 +160,7 @@ begin
wdata_d <= wdata;
if do_write='0' and wren='1' then
last_write <= wdata_d;
if address(3)='0' then -- Voice register
case address(2 downto 0) is
when "000" => freq_lo(to_integer(address(7 downto 4))) <= wdata_d;
@@ -209,20 +211,8 @@ begin
when "00011010" => rdata <= poty;
when "00011011" => rdata <= osc3;
when "00011100" => rdata <= env3;
when others => rdata <= (others => '0');
when others => rdata <= last_write;
end case;
if address(3) = '0' then
case address(2 downto 0) is
when "000" => rdata <= freq_lo(to_integer(address(7 downto 4)));
when "001" => rdata <= freq_hi(to_integer(address(7 downto 4)));
when "010" => rdata <= phase_lo(to_integer(address(7 downto 4)));
when "011" => rdata <= "0000" & phase_hi(to_integer(address(7 downto 4)));
when "100" => rdata <= control(to_integer(address(7 downto 4)));
when "101" => rdata <= att_dec(to_integer(address(7 downto 4)));
when "110" => rdata <= sust_rel(to_integer(address(7 downto 4)));
when others => null;
end case;
end if;
if reset='1' then
freq_lo <= (others => (others => '0'));

4
cores/c64/rtl/sid8580/sid8580.sv
View File

@@ -150,13 +150,14 @@ assign data_out = do_buf;
//assign unsigned_audio = unsigned_filt[18:1];
//assign audio_data = filtered_audio[18:3];// + 15'h4000;//{1'b0, unsigned_audio[17:1]};
reg [7:0] last_wr;
always @(*) begin
case (addr)
5'h19: do_buf = pot_x;
5'h1a: do_buf = pot_y;
5'h1b: do_buf = Misc_Osc3_Random;
5'h1c: do_buf = Misc_Env3;
default: do_buf = 0;
default: do_buf = last_wr;
endcase
end
@@ -192,6 +193,7 @@ always @(posedge clk) begin
end
else begin
if (we) begin
last_wr <= data_in;
case (addr)
5'h00: Voice_1_Freq_lo <= data_in;
5'h01: Voice_1_Freq_hi <= data_in;