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Revision 1464

Added by markw 7 months ago

Correct adc silence threshold for 1x/2x. Correct ADC BITLEN for CIC_STAGES*log2(OVERSAMPLE_RATE)

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atari_chips/pokeyv2/pokeymax.vhd
rst : in std_logic;
adc_lvds_pin : in std_logic;
adc_fb_pin : out std_logic;
adc_output : out std_logic_vector(20 downto 0);
adc_output : out std_logic_vector(19 downto 0);
adc_valid : out std_logic
);
end component;
......
signal enable_reset_min_max : std_logic;
signal adc_valid : std_logic;
signal adc_output : std_logic_vector(20 downto 0);
signal adc_output : std_logic_vector(19 downto 0);
signal adc_lvds_pin : std_logic;
signal adc_fb_pin : std_logic;
......
port map(clk=>CLK49152,reset_n=>reset_n,enable_in=>enable_reset_min_max_pre,enable_out=>enable_reset_min_max);
process(adc_reg,adc_output,adc_valid,ADC_VOLUME_REG)
variable adc_shrunk : signed(20 downto 0);
variable adc_shrunk : signed(19 downto 0);
begin
adc_next <= adc_reg;
if (adc_valid='1') then
adc_shrunk := signed(not(adc_output(20)) & adc_output(19 downto 0));
adc_shrunk := signed(not(adc_output(19)) & adc_output(18 downto 0));
case ADC_VOLUME_REG is
when "01" =>
adc_next <= adc_shrunk(20 downto (20-16+1)); --*1
adc_next <= adc_shrunk(19 downto (19-16+1)); --*1
when "10" =>
adc_next <= adc_shrunk(19 downto (19-16+1)); --*2
adc_next <= adc_shrunk(18 downto (18-16+1)); --*2
when "11" =>
adc_next <= adc_shrunk(18 downto (18-16+1)); --*4
adc_next <= adc_shrunk(17 downto (17-16+1)); --*4
when others =>
adc_next <= (others=>'0');
end case;
end if;
end process;
process(adc_out_signed,adc_min_reg,adc_max_reg,adc_diff_reg,enable_reset_min_max,adc_enabled_reg)
process(adc_out_signed,adc_min_reg,adc_max_reg,adc_diff_reg,enable_reset_min_max,adc_enabled_reg,adc_volume_reg)
variable detected : std_logic;
variable threshold : unsigned(11 downto 0);
begin
adc_min_next <= adc_min_reg;
adc_max_next <= adc_max_reg;
......
if (adc_out_signed(15 downto 4)>adc_max_reg) then
adc_max_next <= adc_out_signed(15 downto 4);
end if;
case adc_volume_reg is
when "01" =>
threshold := to_unsigned(8,12);
when "10" =>
threshold := to_unsigned(16,12);
when others =>
threshold := to_unsigned(32,12);
end case;
if (enable_reset_min_max='1') then
detected := '0';
if (adc_diff_reg>16) then
if (adc_diff_reg>threshold) then
detected := '1';
end if;
if (detected='1' and adc_enabled_reg<63) then
atari_chips/pokeyv2/sigma_delta/sigma_delta_adc.sv
module sigma_delta_adc #(
parameter int OVERSAMPLE_RATE = 1024,
parameter int CIC_STAGES = 2,
parameter int ADC_BITLEN = 21,
parameter int ADC_BITLEN = 20,
parameter bit USE_FIR_COMP = 1,
parameter int FIR_COMP_ALPHA_8 = 2
)(

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