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Gameboy_MiSTer/rtl/gbc_snd.vhd
paulb-nl beacf008b3 Add option to remove audio pops 
Some audio can be inaccurate with this option enabled.
2024-09-16 15:59:30 +02:00

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-- Notes:
-- When the output DAC of each channel is disabled, the real voltage will drift
-- to 0 V at some unknown rate. Here, it is implemented as an immediate return to "0 V".
-- If this is found to not be accurate enough, an additional timer may be added.
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
use work.pBus_savestates.all;
use work.pReg_savestates.all;
library work;
entity gbc_snd is
port (
clk : in std_logic;
ce : in std_logic;
reset : in std_logic;
is_gbc : in std_logic;
remove_pops : in std_logic; -- 0: Accurate output, 1: Toggling DACs will not cause pops but some audio can be inaccurate.
s1_read : in std_logic;
s1_write : in std_logic;
s1_addr : in std_logic_vector(6 downto 0);
s1_readdata : out std_logic_vector(7 downto 0);
s1_writedata : in std_logic_vector(7 downto 0);
snd_left : out std_logic_vector(15 downto 0);
snd_right : out std_logic_vector(15 downto 0);
-- savestates
SaveStateBus_Din : in std_logic_vector(BUS_buswidth-1 downto 0);
SaveStateBus_Adr : in std_logic_vector(BUS_busadr-1 downto 0);
SaveStateBus_wren : in std_logic;
SaveStateBus_rst : in std_logic;
SaveStateBus_Dout : out std_logic_vector(BUS_buswidth-1 downto 0)
);
end gbc_snd;
architecture SYN of gbc_snd is
component apu_dac is
port(
clk : in std_logic;
ce : in std_logic;
dac_en : in std_logic;
dac_invert : in std_logic;
dac_input : in std_logic_vector(3 downto 0);
dac_output : out signed(8 downto 0)
);
end component;
subtype wav_t is std_logic_vector(3 downto 0);
type wav_arr_t is array(0 to 31) of wav_t;
signal en_snd : std_logic; -- Enable at base sound frequency (4.19MHz)
signal en_snd2 : std_logic; -- Enable at clk/2
signal en_snd4 : std_logic; -- Enable at clk/4
signal en_512 : std_logic; -- 512Hz enable
signal en_snden2 : std_logic; -- Enable at clk/2
signal en_snden4 : std_logic; -- Enable at clk/4
signal en_len : std_logic; -- Sample length
signal en_len_r : std_logic;
signal en_env : std_logic; -- Envelope
signal en_sweep : std_logic; -- Sweep
signal snd_enable : std_logic;
signal sq1_swper : std_logic_vector(2 downto 0); -- Sq1 sweep period
signal sq1_swdir : std_logic; -- Sq1 sweep direction
signal sq1_swdir_change : std_logic; -- Sq1 sweep direction-change
signal sq1_swshift : std_logic_vector(2 downto 0); -- Sq1 sweep frequency shift
signal sq1_duty : std_logic_vector(1 downto 0); -- Sq1 duty cycle
signal sq1_slen : std_logic_vector(6 downto 0); -- Sq1 play length
signal sq1_svol : std_logic_vector(3 downto 0); -- Sq1 initial volume
signal sq1_out : std_logic;
signal sq1_envsgn : std_logic; -- Sq1 envelope sign
signal sq1_envsgn_old : std_logic; -- Sq1 old envelope sign (used in zombie mode)
signal sq1_envper : std_logic_vector(2 downto 0); -- Sq1 envelope period
signal sq1_envper_old : std_logic_vector(2 downto 0); -- Sq1 old envelope period (used in zombie mode)
signal sq1_freq : std_logic_vector(10 downto 0); -- Sq1 frequency
signal sq1_trigger : std_logic; -- Sq1 trigger play note
signal sq1_lenchk : std_logic; -- Sq1 length check enable
signal sq1_len_en_change : std_logic; -- Sq1 length off -> on
signal sq1_fr2 : std_logic_vector(10 downto 0); -- Sq1 frequency (shadow copy)
signal sq1_vol : std_logic_vector(3 downto 0); -- Sq1 initial volume
signal sq1_nr2change : std_logic;
signal sq1_lenchange : std_logic;
signal sq1_lenquirk : std_logic;
signal sq1_freqchange : std_logic;
signal sq1_playing : std_logic; -- Sq1 channel active
signal sq1_wav : std_logic_vector(3 downto 0); -- Sq1 output waveform
signal sq1_suppressed : std_logic; -- Sq1 channel 1st sample suppressed when triggered after poweron
signal sq2_out : std_logic;
signal sq2_duty : std_logic_vector(1 downto 0); -- Sq2 duty cycle
signal sq2_slen : std_logic_vector(6 downto 0); -- Sq2 play length
signal sq2_svol : std_logic_vector(3 downto 0); -- Sq2 initial volume
signal sq2_nr2change : std_logic;
signal sq2_lenchange : std_logic;
signal sq2_lenquirk : std_logic;
signal sq2_envsgn : std_logic; -- Sq2 envelope sign
signal sq2_envper : std_logic_vector(2 downto 0); -- Sq2 envelope period
signal sq2_envsgn_old : std_logic; -- Sq2 old envelope sign (used in zombie mode)
signal sq2_envper_old : std_logic_vector(2 downto 0); -- Sq2 old envelope period (used in zombie mode)
signal sq2_freq : std_logic_vector(10 downto 0); -- Sq2 frequency
signal sq2_trigger : std_logic; -- Sq2 trigger play note
signal sq2_lenchk : std_logic; -- Sq2 length check enable
signal sq2_vol : std_logic_vector(3 downto 0); -- Sq2 initial volume
signal sq2_playing : std_logic; -- Sq2 channel active
signal sq2_wav : std_logic_vector(3 downto 0); -- Sq2 output waveform
signal sq2_suppressed : std_logic; -- Sq2 channel 1st sample suppressed when triggered after poweron
signal wav_enable : std_logic; -- Wave enable
signal wav_slen : std_logic_vector(8 downto 0); -- Wave play length
signal wav_lenchange : std_logic;
signal wav_lenquirk : std_logic;
signal wav_volsh : std_logic_vector(1 downto 0); -- Wave volume shift
signal wav_freq : std_logic_vector(10 downto 0); -- Wave frequency
signal wav_trigger : std_logic; -- Wave trigger play note
signal wav_lenchk : std_logic; -- Wave length check enable
signal wav_index : unsigned(4 downto 0); -- Wave current sample index
signal wav_access : unsigned(1 downto 0); -- Wave table access counter used for DMG
signal wav_playing : std_logic;
signal wav_wav : std_logic_vector(3 downto 0); -- Wave output waveform
signal wav_ram : wav_arr_t; -- Wave table
signal wav_wav_r : std_logic_vector(3 downto 0); -- Wave output waveform sample buffer
signal noi_slen : std_logic_vector(6 downto 0);
signal noi_lenchange : std_logic;
signal noi_lenquirk : std_logic;
signal noi_svol : std_logic_vector(3 downto 0);
signal noi_nr2change : std_logic;
signal noi_envsgn : std_logic;
signal noi_envper : std_logic_vector(2 downto 0);
signal noi_envsgn_old : std_logic; -- noi old envelope sign (used in zombie mode)
signal noi_envper_old : std_logic_vector(2 downto 0); -- noi old envelope period (used in zombie mode)
signal noi_freqsh : std_logic_vector(3 downto 0);
signal noi_freqchange : std_logic;
signal noi_short : std_logic;
signal noi_div : std_logic_vector(2 downto 0);
signal noi_trigger : std_logic;
signal noi_lenchk : std_logic;
signal noi_vol : std_logic_vector(3 downto 0); -- Noise initial volume
signal noi_playing : std_logic; -- Noise channel active
signal noi_wav : std_logic_vector(3 downto 0); -- Noise output waveform
signal ch_map : std_logic_vector(7 downto 0);
signal ch_vol : std_logic_vector(7 downto 0);
signal framecnt : integer range 0 to 7 := 0;
signal sq1_trigger_r : std_logic;
signal sq2_trigger_r : std_logic;
signal wav_trigger_r : std_logic;
signal noi_trigger_r : std_logic;
signal s1_write_r : std_logic;
-- savestates
type t_reg_wired_or is array(0 to 6) of std_logic_vector(63 downto 0);
signal reg_wired_or : t_reg_wired_or;
signal SS_Sound1 : std_logic_vector(REG_SAVESTATE_Sound1.upper downto REG_SAVESTATE_Sound1.lower);
signal SS_Sound1_BACK : std_logic_vector(REG_SAVESTATE_Sound1.upper downto REG_SAVESTATE_Sound1.lower);
signal SS_Sound2 : std_logic_vector(REG_SAVESTATE_Sound2.upper downto REG_SAVESTATE_Sound2.lower);
signal SS_Sound2_BACK : std_logic_vector(REG_SAVESTATE_Sound2.upper downto REG_SAVESTATE_Sound2.lower);
signal SS_Sound3 : std_logic_vector(REG_SAVESTATE_Sound3.upper downto REG_SAVESTATE_Sound2.lower);
signal SS_Sound3_BACK : std_logic_vector(REG_SAVESTATE_Sound3.upper downto REG_SAVESTATE_Sound2.lower);
signal SS_Wave1 : std_logic_vector(REG_SAVESTATE_Wave1.upper downto REG_SAVESTATE_Wave1.lower);
signal SS_Wave1_BACK : std_logic_vector(REG_SAVESTATE_Wave1.upper downto REG_SAVESTATE_Wave1.lower);
signal SS_Wave2 : std_logic_vector(REG_SAVESTATE_Wave2.upper downto REG_SAVESTATE_Wave2.lower);
signal SS_Wave2_BACK : std_logic_vector(REG_SAVESTATE_Wave2.upper downto REG_SAVESTATE_Wave2.lower);
signal SS_Wave1_GBC : std_logic_vector(REG_SAVESTATE_Wave1_GBC.upper downto REG_SAVESTATE_Wave1_GBC.lower);
signal SS_Wave2_GBC : std_logic_vector(REG_SAVESTATE_Wave2_GBC.upper downto REG_SAVESTATE_Wave2_GBC.lower);
-- Analog
signal sq1_dac_en : std_logic;
signal sq2_dac_en : std_logic;
-- wav_enable
signal noi_dac_en : std_logic;
signal sq1_dac_out : signed(8 downto 0);
signal sq2_dac_out : signed(8 downto 0);
signal wav_dac_out : signed(8 downto 0);
signal noi_dac_out : signed(8 downto 0);
begin
iREG_SAVESTATE_Sound1 : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Sound1 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(0), SS_Sound1_BACK, SS_Sound1);
iREG_SAVESTATE_Sound2 : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Sound2 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(1), SS_Sound2_BACK, SS_Sound2);
iREG_SAVESTATE_Sound3 : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Sound3 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(2), SS_Sound3_BACK, SS_Sound3);
iREG_SAVESTATE_Wave1 : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Wave1 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(3), SS_Wave1_BACK, SS_Wave1);
iREG_SAVESTATE_Wave2 : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Wave2 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(4), SS_Wave2_BACK, SS_Wave2);
iREG_SAVESTATE_Wave1_GBC : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Wave1 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(5), SS_Wave1_BACK, SS_Wave1_GBC);
iREG_SAVESTATE_Wave2_GBC : entity work.eReg_Savestate generic map ( REG_SAVESTATE_Wave2 ) port map (clk, SaveStateBus_Din, SaveStateBus_Adr, SaveStateBus_wren, SaveStateBus_rst, reg_wired_or(6), SS_Wave2_BACK, SS_Wave2_GBC);
process (reg_wired_or)
variable wired_or : std_logic_vector(63 downto 0);
begin
wired_or := reg_wired_or(0);
for i in 1 to (reg_wired_or'length - 1) loop
wired_or := wired_or or reg_wired_or(i);
end loop;
SaveStateBus_Dout <= wired_or;
end process;
en_snd2 <= en_snd and en_snden2;
en_snd4 <= en_snd and en_snden4;
process (clk)
begin
if rising_edge(clk) then
if reset = '1' then
en_snd <= SS_Sound1(0); --'0';
else
if ce = '1' then
en_snd <= not en_snd;
end if;
end if;
end if;
end process;
SS_Sound1_BACK( 0) <= en_snd;
SS_Sound1_BACK(3 downto 1) <= std_logic_vector(to_unsigned(framecnt, 3));
SS_Sound1_BACK( 4) <= en_len_r ;
SS_Sound1_BACK( 5) <= en_snden2;
SS_Sound1_BACK( 6) <= en_snden4;
SS_Sound1_BACK( 7) <= en_len ;
SS_Sound1_BACK( 8) <= en_env ;
SS_Sound1_BACK( 9) <= en_sweep ;
SS_Sound1_BACK( 10) <= en_512 ;
-- Calculate divided and frame sequencer clock enables
process (clk)
variable clkcnt : unsigned(1 downto 0);
variable cnt_512 : unsigned(12 downto 0);
variable temp_512 : unsigned(13 downto 0);
begin
if rising_edge(clk) then
if reset = '1' then
clkcnt := "00";
cnt_512 := (others => '0');
framecnt <= to_integer(unsigned(SS_Sound1(3 downto 1))); -- 0;
en_len_r <= SS_Sound1( 4); -- '0';
en_snden2 <= SS_Sound1( 5); -- '0';
en_snden4 <= SS_Sound1( 6); -- '0';
en_len <= SS_Sound1( 7); -- '0';
en_env <= SS_Sound1( 8); -- '0';
en_sweep <= SS_Sound1( 9); -- '0';
en_512 <= SS_Sound1(10); -- '0';
elsif snd_enable = '0' then --only clock frame sequencer if sound is enabled, restart at 0
clkcnt := "00";
cnt_512 := (others => '0');
framecnt <= 0;
en_len_r <= '0';
en_snden2 <= '0';
en_snden4 <= '0';
en_len <= '0';
en_env <= '0';
en_sweep <= '0';
en_512 <= '0';
elsif ce = '1' then
-- Base clock divider
if en_snd = '1' then
clkcnt := clkcnt + 1;
if clkcnt(0) = '1' then
en_snden2 <= '1';
else
en_snden2 <= '0';
end if;
if clkcnt = "11" then
en_snden4 <= '1';
else
en_snden4 <= '0';
end if;
end if;
-- Frame sequencer (length, envelope, sweep) clock enables
en_len <= '0';
en_env <= '0';
en_sweep <= '0';
if en_512 = '1' then
en_len_r <= not en_len_r;
if framecnt = 0 or framecnt = 2 or framecnt = 4 or framecnt = 6 then
en_len <= '1';
en_len_r <= not en_len_r;
end if;
if framecnt = 2 or framecnt = 6 then
en_sweep <= '1';
end if;
if framecnt = 7 then
en_env <= '1';
end if;
if framecnt < 7 then
framecnt <= framecnt + 1;
else
framecnt <= 0;
end if;
end if;
--
en_512 <= '0';
if en_snd = '1' then
temp_512 := ('0' & cnt_512) + to_unsigned(1, temp_512'length);
cnt_512 := temp_512(temp_512'high - 1 downto temp_512'low);
en_512 <= temp_512(13);
end if;
end if;
end if;
end process;
SS_Sound1_BACK(13 downto 11) <= sq1_swper ;
SS_Sound1_BACK( 14) <= sq1_swdir ;
SS_Sound1_BACK(17 downto 15) <= sq1_swshift;
SS_Sound1_BACK(19 downto 18) <= sq1_duty ;
--SS_Sound1_BACK(25 downto 20) <= sq1_slen ; size increased, now in sound3 below
SS_Sound1_BACK(25 downto 20) <= (others => '0');
SS_Sound1_BACK(29 downto 26) <= sq1_svol ;
SS_Sound1_BACK( 30) <= sq1_envsgn ;
SS_Sound1_BACK(33 downto 31) <= sq1_envper ;
SS_Sound1_BACK(44 downto 34) <= sq1_freq ;
SS_Sound1_BACK( 45) <= sq1_lenchk ;
SS_Sound1_BACK( 46) <= sq1_trigger;
SS_Sound1_BACK(48 downto 47) <= sq2_duty ;
SS_Sound1_BACK(55 downto 49) <= sq2_slen ;
SS_Sound1_BACK(59 downto 56) <= sq2_svol ;
SS_Sound1_BACK( 60) <= sq2_envsgn ;
SS_Sound1_BACK(63 downto 61) <= sq2_envper ;
SS_Sound2_BACK(10 downto 0) <= sq2_freq ;
SS_Sound2_BACK( 11) <= sq2_lenchk ;
SS_Sound2_BACK( 12) <= sq2_trigger;
SS_Sound2_BACK( 13) <= wav_enable ;
SS_Sound2_BACK(15 downto 14) <= wav_volsh ;
SS_Sound2_BACK(26 downto 16) <= wav_freq ;
SS_Sound2_BACK( 27) <= wav_trigger;
SS_Sound2_BACK( 28) <= wav_lenchk ;
SS_Sound2_BACK(35 downto 29) <= noi_slen ;
SS_Sound2_BACK(39 downto 36) <= noi_svol ;
SS_Sound2_BACK( 40) <= noi_envsgn ;
SS_Sound2_BACK(43 downto 41) <= noi_envper ;
SS_Sound2_BACK(47 downto 44) <= noi_freqsh ;
SS_Sound2_BACK( 48) <= noi_short ;
SS_Sound2_BACK(51 downto 49) <= noi_div ;
SS_Sound2_BACK( 52) <= noi_trigger;
SS_Sound2_BACK( 53) <= noi_lenchk ;
SS_Sound2_BACK( 54) <= snd_enable ;
SS_Sound3_BACK( 7 downto 0) <= ch_map;
SS_Sound3_BACK(15 downto 8) <= ch_vol;
SS_Sound3_BACK(22 downto 16) <= sq1_slen;
wav_ram_savestate : for k in 0 to 15 generate
SS_Wave1_BACK(4*(k+1) - 1 downto 4*k) <= wav_ram(k);
SS_Wave2_BACK(4*(k+1) - 1 downto 4*k) <= wav_ram(k+16);
end generate wav_ram_savestate;
-- Registers
write_registers : process (clk)
variable sq1_trigger_cnt : unsigned(2 downto 0);
variable sq2_trigger_cnt : unsigned(2 downto 0);
variable noi_trigger_cnt : unsigned(2 downto 0);
variable wav_trigger_cnt : unsigned(1 downto 0);
variable wave_index_write : std_logic_vector(3 downto 0);
variable wave_index_lo : integer range 0 to 31 := 0;
begin
if rising_edge(clk) then
-- Registers
if reset = '1' then
-- Reset register values
sq1_swper <= SS_Sound1(13 downto 11); --(others => '0');
sq1_swdir <= SS_Sound1( 14); --'0';
sq1_swshift <= SS_Sound1(17 downto 15); --(others => '0');
sq1_duty <= SS_Sound1(19 downto 18); --(others => '0');
sq1_slen <= SS_Sound3(22 downto 16); --(others => '0');
sq1_svol <= SS_Sound1(29 downto 26); --(others => '0');
sq1_envsgn <= SS_Sound1( 30); --'0';
sq1_envper <= SS_Sound1(33 downto 31); --(others => '0');
sq1_freq <= SS_Sound1(44 downto 34); --(others => '0');
sq1_lenchk <= SS_Sound1( 45); --'0';
sq1_trigger <= SS_Sound1( 46); --'0';
sq2_duty <= SS_Sound1(48 downto 47); --(others => '0');
sq2_slen <= SS_Sound1(55 downto 49); --(others => '0');
sq2_svol <= SS_Sound1(59 downto 56); --(others => '0');
sq2_envsgn <= SS_Sound1( 60); --'0';
sq2_envper <= SS_Sound1(63 downto 61); --(others => '0');
sq2_freq <= SS_Sound2(10 downto 0); --(others => '0');
sq2_lenchk <= SS_Sound2( 11); --'0';
sq2_trigger <= SS_Sound2( 12); --'0';
wav_enable <= SS_Sound2( 13); --'0';
wav_volsh <= SS_Sound2(15 downto 14); --(others => '0');
wav_freq <= SS_Sound2(26 downto 16); --(others => '0');
wav_trigger <= SS_Sound2( 27); --'0';
wav_lenchk <= SS_Sound2( 28); --'0';
sq1_trigger_cnt := (others => '0'); --counter to delay the trigger
sq2_trigger_cnt := (others => '0'); --counter to delay the trigger
wav_trigger_cnt := (others => '0'); --counter to delay the trigger
noi_trigger_cnt := (others => '0'); --counter to delay the trigger
noi_slen <= SS_Sound2(35 downto 29); --(others => '0');
noi_svol <= SS_Sound2(39 downto 36); --(others => '0');
noi_envsgn <= SS_Sound2( 40); --'0';
noi_envper <= SS_Sound2(43 downto 41); --(others => '0');
noi_freqsh <= SS_Sound2(47 downto 44); --(others => '0');
noi_short <= SS_Sound2( 48); --'0';
noi_div <= SS_Sound2(51 downto 49); --(others => '0');
noi_trigger <= SS_Sound2( 52); --'0';
noi_lenchk <= SS_Sound2( 53); --'0';
ch_map <= SS_Sound3( 7 downto 0); --(others => '0');
ch_vol <= SS_Sound3(15 downto 8); --(others => '0');
s1_write_r <= '0';
-- Wave table default values defined in reg_savestates.vhd
if is_gbc = '1' then
for k in 0 to 15 loop
wav_ram(k) <= SS_Wave1_GBC(4*(k+1)-1 downto 4*k);
wav_ram(k+16) <= SS_Wave2_GBC(4*(k+1)-1 downto 4*k);
end loop;
else
for k in 0 to 15 loop
wav_ram(k) <= SS_Wave1(4*(k+1)-1 downto 4*k);
wav_ram(k+16) <= SS_Wave2(4*(k+1)-1 downto 4*k);
end loop;
end if;
snd_enable <= SS_Sound2(54); -- '0';
elsif ce = '1' then
if en_snd2 = '1' then
if sq1_trigger_cnt = "000" then
sq1_trigger <= '0';
else
sq1_trigger_cnt := sq1_trigger_cnt - 1;
end if;
if sq2_trigger_cnt = "000" then
sq2_trigger <= '0';
else
sq2_trigger_cnt := sq2_trigger_cnt - 1;
end if;
if wav_trigger_cnt = "00" then
wav_trigger <= '0';
else
wav_trigger_cnt := wav_trigger_cnt - 1;
end if;
if noi_trigger_cnt = "000" then
noi_trigger <= '0';
else
noi_trigger_cnt := noi_trigger_cnt - 1;
end if;
end if;
sq2_nr2change <= '0';
sq1_nr2change <= '0';
noi_nr2change <= '0';
noi_freqchange <= '0';
sq2_lenchange <= '0';
sq1_lenchange <= '0';
wav_lenchange <= '0';
noi_lenchange <= '0';
sq1_lenquirk <= '0';
sq2_lenquirk <= '0';
wav_lenquirk <= '0';
noi_lenquirk <= '0';
sq1_swdir_change <= '0';
if sq1_freqchange = '1' then
sq1_freq <= sq1_fr2;
end if;
s1_write_r <= s1_write; -- check posedge
-- write to registers ignored when the apu is off , Wave memory can be read back freely , NR52 power control is always writable
if s1_write = '1' and s1_write_r = '0' and (snd_enable = '1' or s1_addr = "0100110" or s1_addr(5 downto 4) = "11" or (is_gbc = '0' and (s1_addr = "0010001" or s1_addr = "0010110" or s1_addr = "0011011" or s1_addr = "0100000" ))) then
case s1_addr is
-- Square 1
when "0010000" => -- NR10 FF10 -PPP NSSS Sweep period, negate, shift
sq1_swper <= s1_writedata(6 downto 4);
if s1_writedata(3) = '0' then -- only neg to pos, 1 -> 0
sq1_swdir_change <= '1';
end if;
sq1_swdir <= s1_writedata(3);
sq1_swshift <= s1_writedata(2 downto 0);
when "0010001" => -- NR11 FF11 DDLL LLLL Duty, Length load (64-L)
if snd_enable = '1' then
sq1_duty <= s1_writedata(7 downto 6);
end if;
sq1_slen <= std_logic_vector("1000000" - unsigned(s1_writedata(5 downto 0)));
sq1_lenchange <= '1';
when "0010010" => -- NR12 FF12 VVVV APPP Starting volume, Envelope add mode, period
-- zombie mode copy old values
sq1_envsgn_old <= sq1_envsgn;
sq1_envper_old <= sq1_envper;
-- write to registers
sq1_nr2change <= '1';
sq1_svol <= s1_writedata(7 downto 4);
sq1_envsgn <= s1_writedata(3);
sq1_envper <= s1_writedata(2 downto 0);
when "0010011" => -- NR13 FF13 FFFF FFFF Frequency LSB
sq1_freq(7 downto 0) <= s1_writedata;
when "0010100" => -- NR14 FF14 TL-- -FFF Trigger, Length enable, Frequency MSB
sq1_trigger <= s1_writedata(7);
if s1_writedata(7) = '1' then
if sq1_playing = '1' then
sq1_trigger_cnt := "010"; -- --according to sameboy : Timing quirk: if already active, sound starts 2 (2MHz) ticks earlier.
else
sq1_trigger_cnt := "100";
end if;
end if;
if sq1_lenchk = '0' and s1_writedata(6) = '1' and en_len_r = '1' then
sq1_lenquirk <= '1';
end if;
sq1_lenchk <= s1_writedata(6);
sq1_freq(10 downto 8) <= s1_writedata(2 downto 0);
-- Square 2
when "0010110" => -- NR21 FF16 DDLL LLLL Duty, Length load (64-L)
if snd_enable = '1' then
sq2_duty <= s1_writedata(7 downto 6);
end if;
sq2_slen <= std_logic_vector("1000000" - unsigned(s1_writedata(5 downto 0)));
sq2_lenchange <= '1';
when "0010111" => -- NR22 FF17 VVVV APPP Starting volume, Envelope add mode, period
-- zombie mode copy old values
sq2_envsgn_old <= sq2_envsgn;
sq2_envper_old <= sq2_envper;
-- write to registers
sq2_svol <= s1_writedata(7 downto 4);
sq2_nr2change <= '1';
sq2_envsgn <= s1_writedata(3);
sq2_envper <= s1_writedata(2 downto 0);
when "0011000" => -- NR23 FF18 FFFF FFFF Frequency LSB
sq2_freq(7 downto 0) <= s1_writedata;
when "0011001" => -- NR24 FF19 TL-- -FFF Trigger, Length enable, Frequency MSB
sq2_trigger <= s1_writedata(7);
if s1_writedata(7) = '1' then
if sq2_playing = '1' then
sq2_trigger_cnt := "010"; -- according to sameboy : Timing quirk: if already active, sound starts 2 (2MHz) ticks earlier.
else
sq2_trigger_cnt := "100";
end if;
end if;
if sq2_lenchk = '0' and s1_writedata(6) = '1' and en_len_r = '1' then
sq2_lenquirk <= '1';
end if;
sq2_lenchk <= s1_writedata(6);
sq2_freq(10 downto 8) <= s1_writedata(2 downto 0);
-- Wave
when "0011010" => -- NR30 FF1A E--- ---- DAC power
wav_enable <= s1_writedata(7);
when "0011011" => -- NR31 FF1B LLLL LLLL Length load (256-L)
-- wav_slen <= s1_writedata;
wav_slen <= std_logic_vector("100000000" - unsigned(s1_writedata));
wav_lenchange <= '1';
when "0011100" => -- NR32 FF1C -VV- ---- Volume code (00=0%, 01=100%, 10=50%, 11=25%)
wav_volsh <= s1_writedata(6 downto 5);
when "0011101" => -- NR33 FF1D FFFF FFFF Frequency LSB
wav_freq(7 downto 0) <= s1_writedata;
when "0011110" => -- NR34 FF1E TL-- -FFF Trigger, Length enable, Frequency MSB
wav_trigger <= s1_writedata(7);
if s1_writedata(7) = '1' then
wav_trigger_cnt := "10";
end if;
if wav_lenchk = '0' and s1_writedata(6) = '1' and en_len_r = '1' then
wav_lenquirk <= '1';
end if;
wav_lenchk <= s1_writedata(6);
wav_freq(10 downto 8) <= s1_writedata(2 downto 0);
-- Noise
when "0100000" => -- NR41 FF20 --LL LLLL Length load (64-L)
noi_slen <= std_logic_vector("1000000" - unsigned(s1_writedata(5 downto 0)));
noi_lenchange <= '1';
when "0100001" => -- NR42 FF21 VVVV APPP Starting volume, Envelope add mode, period
-- zombie mode copy old values
noi_envsgn_old <= noi_envsgn;
noi_envper_old <= noi_envper;
-- write to registers
noi_svol <= s1_writedata(7 downto 4);
noi_nr2change <= '1';
noi_envsgn <= s1_writedata(3);
noi_envper <= s1_writedata(2 downto 0);
when "0100010" => -- NR43 FF22 SSSS WDDD Clock shift, Width mode of LFSR, Divisor code
noi_freqsh <= s1_writedata(7 downto 4);
noi_short <= s1_writedata(3);
noi_div <= s1_writedata(2 downto 0);
noi_freqchange <= '1';
when "0100011" => -- NR44 FF23 TL-- ---- Trigger, Length enable
noi_trigger <= s1_writedata(7);
if s1_writedata(7) = '1' then
if noi_playing = '0' then
noi_trigger_cnt := "010";
else
noi_trigger_cnt := "100"; --noi seems to start later instead of early if already playing
end if;
end if;
if noi_lenchk = '0' and s1_writedata(6) = '1' and en_len_r = '1' then
noi_lenquirk <= '1';
end if;
noi_lenchk <= s1_writedata(6);
-- Control/Status
when "0100100" => -- NR50 FF24
ch_vol <= s1_writedata;
when "0100101" => -- NR51 FF25
ch_map <= s1_writedata;
-- NR52 FF26 P--- NW21 Power control/status, Channel length statuses
when "0100110" =>
snd_enable <= s1_writedata(7);
if s1_writedata(7) = '0' then
-- Reset register values
sq1_swper <= (others => '0');
sq1_swdir <= '0';
sq1_swshift <= (others => '0');
sq1_duty <= (others => '0');
sq1_svol <= (others => '0');
sq1_envsgn <= '0';
sq1_envper <= (others => '0');
sq1_freq <= (others => '0');
sq1_lenchk <= '0';
sq1_trigger <= '0';
sq2_duty <= (others => '0');
sq2_svol <= (others => '0');
sq2_envsgn <= '0';
sq2_envper <= (others => '0');
sq2_freq <= (others => '0');
sq2_lenchk <= '0';
sq2_trigger <= '0';
wav_enable <= '0';
wav_volsh <= (others => '0');
wav_freq <= (others => '0');
wav_trigger <= '0';
wav_lenchk <= '0';
sq1_trigger_cnt := (others => '0'); --counter to leave the trigger high for a few cycles
sq2_trigger_cnt := (others => '0'); --counter to leave the trigger high for a few cycles
wav_trigger_cnt := (others => '0'); --counter to leave the trigger high for a few cycles
noi_trigger_cnt := (others => '0'); --counter to leave the trigger high for a few cycles
noi_svol <= (others => '0');
noi_envsgn <= '0';
noi_envper <= (others => '0');
noi_freqsh <= (others => '0');
noi_short <= '0';
noi_div <= (others => '0');
noi_trigger <= '0';
noi_lenchk <= '0';
ch_map <= (others => '0');
ch_vol <= (others => '0');
s1_write_r <= '0';
if is_gbc = '1' then
sq1_slen <= (others => '0');
sq2_slen <= (others => '0');
wav_slen <= (others => '0');
noi_slen <= (others => '0');
end if;
end if;
-- Wave Table
when "0110000" | "0110001" | "0110010" | "0110011" | "0110100" | "0110101" | "0110110" | "0110111" | "0111000" | "0111001" | "0111010" | "0111011" | "0111100" | "0111101" | "0111110" | "0111111" => -- FF30 to FF3F
if wav_playing = '1' then
wave_index_write := std_logic_vector(wav_index(4 downto 1));
else
wave_index_write := s1_addr(3 downto 0);
end if;
if is_gbc = '1' or wav_access > 0 or wav_playing = '0' then
wave_index_lo := to_integer(unsigned(wave_index_write & '0'));
wav_ram(wave_index_lo) <= s1_writedata(7 downto 4);
wav_ram(wave_index_lo + 1) <= s1_writedata(3 downto 0);
end if;
when others =>
null;
end case;
end if;
end if;
end if;
end process write_registers;
read_registers : process (s1_addr, sq1_swper, sq1_swdir, sq1_swshift, sq1_duty, sq1_svol, sq1_envsgn, sq1_envper, sq1_lenchk,
noi_playing, wav_playing, sq2_playing, sq1_playing, wav_enable, wav_volsh, wav_ram, wav_index, wav_access,
sq2_duty, sq2_svol, sq2_envsgn, sq2_envper, sq2_lenchk, snd_enable, wav_lenchk, noi_svol, noi_envsgn, noi_envper,
noi_freqsh, noi_short, noi_div, noi_lenchk, ch_vol, ch_map, is_gbc, sq1_wav, sq2_wav, wav_wav, noi_wav)
variable wave_index_read : std_logic_vector(3 downto 0);
variable wave_index_lo : integer range 0 to 31 := 0;
begin
case s1_addr is
-- Square 1
when "0010000" => -- NR10 FF10 -PPP NSSS Sweep period, negate, shift
s1_readdata <= '1' & sq1_swper & sq1_swdir & sq1_swshift;
when "0010001" => -- NR11 FF11 DDLL LLLL Duty, Length load (64-L)
s1_readdata <= sq1_duty & "111111";
when "0010010" => -- NR12 FF12 VVVV APPP Starting volume, Envelope add mode, period
s1_readdata <= sq1_svol & sq1_envsgn & sq1_envper;
when "0010011" => -- NR13 FF13 FFFF FFFF Frequency LSB
s1_readdata <= X"FF";
when "0010100" => -- NR14 FF14 TL-- -FFF Trigger, Length enable, Frequency MSB
s1_readdata <= '1' & sq1_lenchk & "111111";
-- Square 2
when "0010110" => -- NR21 FF16 DDLL LLLL Duty, Length load (64-L)
s1_readdata <= sq2_duty & "111111";
when "0010111" => -- NR22 FF17 VVVV APPP Starting volume, Envelope add mode, period
s1_readdata <= sq2_svol & sq2_envsgn & sq2_envper;
when "0011000" => -- NR23 FF18 FFFF FFFF Frequency LSB
s1_readdata <= X"FF";
when "0011001" => -- NR24 FF19 TL-- -FFF Trigger, Length enable, Frequency MSB
s1_readdata <= '1' & sq2_lenchk & "111111";
-- Wave
when "0011010" => -- NR30 FF1A E--- ---- DAC power
s1_readdata <= wav_enable & "1111111";
when "0011011" => -- NR31 FF1B LLLL LLLL Length load (256-L)
s1_readdata <= X"FF";
when "0011100" => -- NR32 FF1C -VV- ---- Volume code (00=0%, 01=100%, 10=50%, 11=25%)
s1_readdata <= '1' & wav_volsh & "11111";
when "0011101" => -- NR33 FF1D FFFF FFFF Frequency LSB
s1_readdata <= X"FF";
when "0011110" => -- NR34 FF1E TL-- -FFF Trigger, Length enable, Frequency MSB
s1_readdata <= '1' & wav_lenchk & "111111";
-- Noise
when "0100000" => -- NR41 FF20 --LL LLLL Length load (64-L)
s1_readdata <= X"FF";
when "0100001" => -- NR42 FF21 VVVV APPP Starting volume, Envelope add mode, period
s1_readdata <= noi_svol & noi_envsgn & noi_envper;
when "0100010" => -- NR43 FF22 SSSS WDDD Clock shift, Width mode of LFSR, Divisor code
s1_readdata <= noi_freqsh & noi_short & noi_div;
when "0100011" => -- NR44 FF23 TL-- ---- Trigger, Length enable
s1_readdata <= '1' & noi_lenchk & "111111";
-- Wave Table
when "0110000" | "0110001" | "0110010" | "0110011" | "0110100" | "0110101" | "0110110" | "0110111" | "0111000" | "0111001" | "0111010" | "0111011" | "0111100" | "0111101" | "0111110" | "0111111" => -- FF30 to FF3F
if wav_playing = '1' then
wave_index_read := std_logic_vector(wav_index(4 downto 1));
else
wave_index_read := s1_addr(3 downto 0);
end if;
if is_gbc = '1' or wav_access > 0 or wav_playing = '0' then
wave_index_lo := to_integer(unsigned(wave_index_read & '0'));
s1_readdata <= wav_ram(wave_index_lo) & wav_ram(wave_index_lo+1);
else
s1_readdata <= X"FF";
end if;
-- Control/Status
when "0100100" =>
s1_readdata <= ch_vol; -- NR50 FF24
when "0100101" =>
s1_readdata <= ch_map; -- NR51 FF25
when "0100110" => -- NR52 FF26 P--- NW21 Power control/status, Channel length statuses
s1_readdata <= snd_enable & "111" & noi_playing & wav_playing & sq2_playing & sq1_playing;
-- Undocumented Registers
when "1110110" => -- PCM12 FF76
if is_gbc = '1' then
s1_readdata <= (others => '0');
if sq2_playing = '1' then
s1_readdata(7 downto 4) <= sq2_wav;
end if;
if sq1_playing = '1' then
s1_readdata(3 downto 0) <= sq1_wav;
end if;
else
s1_readdata <= X"FF";
end if;
when "1110111" => -- PCM34 FF77
if is_gbc = '1' then
s1_readdata <= (others => '0');
if noi_playing = '1' then
s1_readdata(7 downto 4) <= noi_wav;
end if;
if wav_playing = '1' then
s1_readdata(3 downto 0) <= wav_wav;
end if;
else
s1_readdata <= X"FF";
end if;
when others =>
s1_readdata <= X"FF";
end case;
end process read_registers;
SS_Sound3_BACK( 23) <= sq1_playing;
SS_Sound3_BACK(34 downto 24) <= sq1_fr2;
SS_Sound3_BACK(38 downto 35) <= sq1_vol;
SS_Sound3_BACK( 39) <= sq2_playing;
SS_Sound3_BACK(43 downto 40) <= sq2_vol;
SS_Sound3_BACK(45 downto 44) <= "00"; -- unused
SS_Sound3_BACK(49 downto 46) <= wav_wav_r;
SS_Sound3_BACK( 50) <= wav_playing;
SS_Sound3_BACK(55 downto 51) <= std_logic_vector(wav_index);
SS_Sound3_BACK(57 downto 56) <= std_logic_vector(wav_access);
SS_Sound3_BACK( 58) <= noi_playing;
SS_Sound3_BACK(62 downto 59) <= noi_vol;
square1 : process(clk, sq1_vol, sq1_svol, sq1_envsgn, sq1_out, sq1_suppressed)
constant duty_0 : std_logic_vector(0 to 7) := "00000001";
constant duty_1 : std_logic_vector(0 to 7) := "10000001";
constant duty_2 : std_logic_vector(0 to 7) := "10000111";
constant duty_3 : std_logic_vector(0 to 7) := "01111110";
variable sq1_fcnt : unsigned(10 downto 0);
variable sq1_phase : integer range 0 to 7;
variable sq1_len : std_logic_vector(6 downto 0);
variable sq1_envcnt : std_logic_vector(3 downto 0); -- Sq1 envelope timer count
variable sq1_swcnt : std_logic_vector(3 downto 0); -- Sq1 sweep timer count
variable sq1_swoffs : unsigned(11 downto 0);
variable sq1_swfr : unsigned(11 downto 0);
variable sq1_sweep_en : std_logic;
variable sweep_calculate : std_logic;
variable sweep_update : std_logic;
variable sweep_negate : std_logic;
variable sq1_sduty : std_logic_vector(1 downto 0); -- Sq1 duty cycle shadow register
variable sq1_trigger_freq : std_logic_vector(10 downto 0);
variable acc_fcnt : unsigned(11 downto 0);
variable tmp_volume : unsigned(7 downto 0); -- used in zombie mode
begin
sq1_dac_en <= '1';
if sq1_svol & sq1_envsgn = "00000" then
sq1_dac_en <= '0';
end if;
if sq1_out = '1' and sq1_suppressed = '0' then
sq1_wav <= sq1_vol;
else
sq1_wav <= "0000";
end if;
if rising_edge(clk) then
if reset = '1' then
sq1_playing <= SS_Sound3( 23); -- '0';
sq1_fr2 <= SS_Sound3(34 downto 24); -- (others => '0');
sq1_fcnt := (others => '0');
sq1_phase := 0;
sq1_vol <= SS_Sound3(38 downto 35); -- "0000";
sq1_envcnt := "0000";
sq1_swcnt := "0000";
sq1_swoffs := (others => '0');
sq1_swfr := (others => '0');
sq1_out <= '0';
sq1_suppressed <= '1';
sq1_sduty := (others => '0');
sweep_calculate := '0';
sweep_update := '0';
sq1_sweep_en := '0';
sweep_negate := '0';
sq1_len := (others => '0');
sq1_trigger_r <= '0';
sq1_trigger_freq := (others => '0');
elsif ce = '1' then
if sq1_lenchange = '1' then
sq1_len := sq1_slen;
end if;
-- used to detect trigger negedge
sq1_trigger_r <= sq1_trigger;
if snd_enable = '1' then
if en_snd4 = '1' then
-- Sq1 frequency timer Frequency = 131072/(2048-x) Hz
if sq1_playing = '1' then
acc_fcnt := ('0' & sq1_fcnt) + to_unsigned(1, acc_fcnt'length);
if acc_fcnt(acc_fcnt'high) = '1' then
sq1_suppressed <= '0';
if (sq1_phase < 7) then sq1_phase := sq1_phase + 1; else sq1_phase := 0; end if;
sq1_fcnt := unsigned(sq1_freq);
sq1_sduty := sq1_duty; -- only change duty after the sample is finished
else
sq1_fcnt := acc_fcnt(sq1_fcnt'range);
end if;
end if;
case sq1_sduty is
when "00" => sq1_out <= duty_0(sq1_phase);
when "01" => sq1_out <= duty_1(sq1_phase);
when "10" => sq1_out <= duty_2(sq1_phase);
when "11" => sq1_out <= duty_3(sq1_phase);
when others => null;
end case;
end if;
-- Length counter
if en_len = '1' or sq1_lenquirk = '1' then
if sq1_len > 0 and sq1_lenchk = '1' then
sq1_len := std_logic_vector(unsigned(sq1_len) - 1);
end if;
end if;
-- Sweep processing
-- sweep counter
if en_sweep = '1' then
sq1_swcnt := std_logic_vector(unsigned(sq1_swcnt) - 1);
if sq1_swcnt = 0 then
-- reload counter with period
if sq1_swper = "000" then
sq1_swcnt := "1000"; -- set to 8
else
sq1_swcnt := '0' & sq1_swper; -- set to period
end if;
-- check if update needed
if sq1_sweep_en = '1' and sq1_swper /= "000" then
sweep_calculate := '1';
sweep_update := '1';
end if;
end if;
end if;
sq1_freqchange <= '0';
if sq1_sweep_en = '1' then
-- Calculate next sweep frequency
if sweep_calculate = '1' then
case sq1_swshift is
when "000" => sq1_swoffs := unsigned('0' & sq1_fr2);
when "001" => sq1_swoffs := "00" & unsigned(sq1_fr2(10 downto 1));
when "010" => sq1_swoffs := "000" & unsigned(sq1_fr2(10 downto 2));
when "011" => sq1_swoffs := "0000" & unsigned(sq1_fr2(10 downto 3));
when "100" => sq1_swoffs := "00000" & unsigned(sq1_fr2(10 downto 4));
when "101" => sq1_swoffs := "000000" & unsigned(sq1_fr2(10 downto 5));
when "110" => sq1_swoffs := "0000000" & unsigned(sq1_fr2(10 downto 6));
when "111" => sq1_swoffs := "00000000" & unsigned(sq1_fr2(10 downto 7));
when others => sq1_swoffs := unsigned('0' & sq1_fr2);
end case;
if sq1_swdir = '1' then
sq1_swfr := ('0' & unsigned(sq1_fr2)) - sq1_swoffs;
sweep_negate := '1';
else
sq1_swfr := ('0' & unsigned(sq1_fr2)) + sq1_swoffs;
sweep_negate := '0';
end if;
sweep_calculate := '0';
end if;
-- update registers, and calculate next frequency
if sweep_update = '1' then
sweep_update := '0';
if (sq1_swper /= "000" and sq1_swshift /= "000") then
sq1_fr2 <= std_logic_vector(sq1_swfr(10 downto 0));
sq1_freqchange <= '1';
sweep_calculate := '1'; -- when updating calculate 2nd time
end if;
end if;
end if;
if sq1_playing = '1' then
-- Envelope counter
if en_env = '1' and sq1_envper /= "000" then
sq1_envcnt := std_logic_vector(unsigned(sq1_envcnt) - 1); -- decrement counter
if sq1_envcnt = 0 then
if sq1_envsgn = '1' then
if sq1_vol /= "1111" then -- sq1_vol < 15
sq1_vol <= std_logic_vector(unsigned(sq1_vol) + 1);
end if;
else
if sq1_vol /= "0000" then -- sq1_vol >
sq1_vol <= std_logic_vector(unsigned(sq1_vol) - 1);
end if;
end if;
-- reload counter with period
if sq1_envper = "000" then
sq1_envcnt := "1000"; -- set to 8
else
sq1_envcnt := '0' & sq1_envper; -- set to period
end if;
end if;
end if;
-- Check for end of playing conditions
if (sq1_lenchk = '1' and sq1_len = 0) -- Play length timer overrun
or (sq1_sweep_en = '1' and sq1_swfr(11) = '1') -- Sweep frequency overrun
or (sq1_sweep_en = '1' and sq1_swdir_change = '1' and sweep_negate = '1') -- sweep direction change after trigger
then
sq1_playing <= '0';
sq1_envcnt := (others => '0');
sq1_swcnt := (others => '0');
sq1_swfr := (others => '0');
sq1_sweep_en := '0';
end if;
end if;
if ((sq1_trigger_r = '1' and sq1_trigger = '0') or sq1_nr2change = '1') and sq1_playing = '1' then -- falling edge of trigger
-- using sameboy's logic
-- "zombie" mode
tmp_volume := "0000" & unsigned(sq1_vol);
if sq1_envsgn = '1' then
tmp_volume := tmp_volume + 1;
end if;
if (sq1_envsgn xor sq1_envsgn_old) = '1' then
tmp_volume := X"10" - tmp_volume;
end if;
if (sq1_envper /= "000") and (sq1_envper_old = "000") and (tmp_volume /= "00000000") and (sq1_envsgn = '0') then
tmp_volume := tmp_volume - 1;
end if;
if (sq1_envper_old /= "000") and sq1_envsgn = '1' then
tmp_volume := tmp_volume - 1;
end if;
sq1_vol <= std_logic_vector(tmp_volume(3 downto 0));
-- "zombie" mode
-- check if dac is enabled
if sq1_svol = "00000" and sq1_envsgn = '0' then -- dac disabled
sq1_playing <= '0';
end if;
end if;
-- if sound was triggered and already playing reset/stop frequency counter
if sq1_trigger = '1' and sq1_playing = '1' then
sq1_fcnt := (others => '0');
end if;
if sq1_trigger_r = '0' and sq1_trigger = '1' then -- rising edge of trigger
sq1_trigger_freq := sq1_freq; -- keep copy of frequency to avoid change while delaying trigger
end if;
-- Check sample trigger and start playing
if sq1_trigger_r = '1' and sq1_trigger = '0' then -- falling edge of trigger
-- from sameboy:
-- Current sample index remains unchanged when restarting channels 1 or 2. It is only reset by turning the APU off.
if sq1_playing = '0' then
sq1_suppressed <= '1'; -- suppress 1st sample if channel wasn't active
end if;
sq1_vol <= sq1_svol;
sq1_fr2 <= sq1_freq; -- shadow frequency register for sweep unit
sq1_sweep_en := '0';
if (sq1_swper /= "000" or sq1_swshift /= "000") then -- sweep unit enabled ?
sq1_sweep_en := '1';
end if;
---- sweep quirks ---
if sq1_swshift /= "000" then
sweep_calculate := '1';
end if;
if sq1_swper = "000" then
sq1_swcnt := "1000"; -- set to 8
else
sq1_swcnt := '0' & sq1_swper; -- set to period
end if;
sweep_negate := '0';
---- sweep quirks ---
sq1_fcnt := unsigned(sq1_trigger_freq);
if not (sq1_svol = "00000" and sq1_envsgn = '0') then -- dac enabled
sq1_playing <= '1';
end if;
-- reload envelope counter with period
if sq1_envper = "000" then
sq1_envcnt := "1000"; -- set to 8
else
sq1_envcnt := '0' & sq1_envper; -- set to period
end if;
if sq1_len = 0 then -- trigger quirks
if sq1_lenchk = '1' and en_len_r = '1' then
sq1_len := "0111111"; -- 63
else
sq1_len := "1000000"; -- 64
end if;
end if;
end if;
else
sq1_playing <= '0';
sq1_fr2 <= (others => '0');
sq1_fcnt := (others => '0');
sq1_phase := 0;
sq1_vol <= "0000";
sq1_envcnt := "0000";
sq1_swcnt := "0000";
sq1_swoffs := (others => '0');
sq1_swfr := (others => '0');
sq1_out <= '0';
sq1_suppressed <= '1';
sq1_sduty := (others => '0');
sweep_calculate := '0';
sweep_update := '0';
sq1_sweep_en := '0';
sweep_negate := '0';
if is_gbc = '1' then
sq1_len := (others => '0');
end if;
sq1_trigger_r <= '0';
end if;
end if;
end if;
end process square1;
square2 : process(clk, sq2_vol, sq2_svol, sq2_envsgn, sq2_out, sq2_suppressed)
constant duty_0 : std_logic_vector(0 to 7) := "00000001";
constant duty_1 : std_logic_vector(0 to 7) := "10000001";
constant duty_2 : std_logic_vector(0 to 7) := "10000111";
constant duty_3 : std_logic_vector(0 to 7) := "01111110";
variable sq2_fcnt : unsigned(10 downto 0);
variable sq2_phase : integer range 0 to 7;
variable sq2_len : std_logic_vector(6 downto 0);
variable sq2_envcnt : std_logic_vector(3 downto 0); -- Sq2 envelope timer count
variable sq2_sduty : std_logic_vector(1 downto 0); -- Sq2 duty cycle shadow register
variable sq2_trigger_freq : std_logic_vector(10 downto 0);
variable acc_fcnt : unsigned(11 downto 0);
variable tmp_volume : unsigned(7 downto 0); -- used in zombie mode
begin
sq2_dac_en <= '1';
if sq2_svol & sq2_envsgn = "00000" then
sq2_dac_en <= '0';
end if;
if sq2_out = '1' and sq2_suppressed = '0' then
sq2_wav <= sq2_vol;
else
sq2_wav <= "0000";
end if;
if rising_edge(clk) then
if reset = '1' then
sq2_playing <= SS_Sound3( 39); -- '0';
sq2_fcnt := (others => '0');
sq2_phase := 0;
sq2_vol <= SS_Sound3(43 downto 40); -- "0000";
sq2_envcnt := "0000";
sq2_out <= '0';
sq2_suppressed <= '1';
sq2_sduty := (others => '0');
sq2_len := (others => '0');
sq2_trigger_r <= '0';
sq2_trigger_freq := (others => '0');
elsif ce = '1' then
if sq2_lenchange = '1' then
sq2_len := sq2_slen;
end if;
sq2_trigger_r <= sq2_trigger;
if snd_enable = '1' then
if en_snd4 = '1' then
-- Sq2 frequency timer Frequency = 131072/(2048-x) Hz
if sq2_playing = '1' then
acc_fcnt := ('0' & sq2_fcnt) + to_unsigned(1, acc_fcnt'length);
if acc_fcnt(acc_fcnt'high) = '1' then
sq2_suppressed <= '0';
if (sq2_phase < 7) then sq2_phase := sq2_phase + 1; else sq2_phase := 0; end if;
sq2_fcnt := unsigned(sq2_freq);
sq2_sduty := sq2_duty; -- only change duty after the sample is finished
else
sq2_fcnt := acc_fcnt(sq2_fcnt'range);
end if;
end if;
case sq2_sduty is
when "00" => sq2_out <= duty_0(sq2_phase);
when "01" => sq2_out <= duty_1(sq2_phase);
when "10" => sq2_out <= duty_2(sq2_phase);
when "11" => sq2_out <= duty_3(sq2_phase);
when others => null;
end case;
end if;
-- Length counter
if en_len = '1' or sq2_lenquirk = '1' then
if sq2_len > 0 and sq2_lenchk = '1' then
sq2_len := std_logic_vector(unsigned(sq2_len) - 1);
end if;
end if;
if sq2_playing = '1' then
-- Envelope counter
if en_env = '1' and sq2_envper /= "000" then
sq2_envcnt := std_logic_vector(unsigned(sq2_envcnt) - 1); -- decrement counter
if sq2_envcnt = 0 then
if sq2_envsgn = '1' then
if sq2_vol /= "1111" then -- sq2_vol < 15
sq2_vol <= std_logic_vector(unsigned(sq2_vol) + 1);
end if;
else
if sq2_vol /= "0000" then -- sq2_vol > 0
sq2_vol <= std_logic_vector(unsigned(sq2_vol) - 1);
end if;
end if;
-- reload counter with period
if sq2_envper = "000" then
sq2_envcnt := "1000"; -- set to 8
else
sq2_envcnt := '0' & sq2_envper; -- set to period
end if;
end if;
end if;
-- Check for end of playing conditions
-- if sq2_vol = X"0" -- Volume == 0
if sq2_lenchk = '1' and sq2_len = 0 -- Play length timer overrun
then
sq2_playing <= '0';
sq2_envcnt := "0000";
end if;
end if;
if ((sq2_trigger_r = '1' and sq2_trigger = '0') or sq2_nr2change = '1') and sq2_playing = '1' then -- falling edge of trigger
-- using sameboy's logic
-- "zombie" mode
tmp_volume := "0000" & unsigned(sq2_vol);
if sq2_envsgn = '1' then
tmp_volume := tmp_volume + 1;
end if;
if (sq2_envsgn xor sq2_envsgn_old) = '1' then
tmp_volume := X"10" - tmp_volume;
end if;
if (sq2_envper /= "000") and (sq2_envper_old = "000") and (tmp_volume /= "00000000") and (sq2_envsgn = '0') then
tmp_volume := tmp_volume - 1;
end if;
if (sq2_envper_old /= "000") and sq2_envsgn = '1' then
tmp_volume := tmp_volume - 1;
end if;
sq2_vol <= std_logic_vector(tmp_volume(3 downto 0));
-- "zombie" mode
-- check if dac is enabled
if sq2_svol = "00000" and sq2_envsgn = '0' then -- dac disabled
sq2_playing <= '0';
end if;
end if;
-- if sound was triggered and already playing reset/stop frequency counter
if sq2_trigger = '1' and sq2_playing = '1' then
sq2_fcnt := (others => '0');
end if;
if sq2_trigger_r = '0' and sq2_trigger = '1' then -- rising edge of trigger
sq2_trigger_freq := sq2_freq; -- keep copy of frequency to avoid change while delaying trigger
end if;
-- Check sample trigger and start playing
if sq2_trigger_r = '1' and sq2_trigger = '0' then -- falling edge of trigger
-- from sameboy:
-- Current sample index remains unchanged when restarting channels 1 or 2. It is only reset by turning the APU off.
if sq2_playing = '0' then
sq2_suppressed <= '1'; -- suppress 1st sample if channel wasn't active
end if;
sq2_vol <= sq2_svol;
sq2_fcnt := unsigned(sq2_trigger_freq);
if not (sq2_svol = "00000" and sq2_envsgn = '0') then -- dac enabled
sq2_playing <= '1';
end if;
-- reload envelope counter with period
if sq2_envper = "000" then
sq2_envcnt := "1000"; -- set to 8
else
sq2_envcnt := '0' & sq2_envper; -- set to period
end if;
if sq2_len = 0 then -- trigger quirks
if sq2_lenchk = '1' and en_len_r = '1' then
sq2_len := "0111111"; -- 63
else
sq2_len := "1000000"; -- 64
end if;
end if;
end if;
else
sq2_playing <= '0';
sq2_fcnt := (others => '0');
sq2_phase := 0;
sq2_vol <= "0000";
sq2_envcnt := "0000";
sq2_out <= '0';
sq2_suppressed <= '1';
sq2_sduty := (others => '0');
if is_gbc = '1' then
sq2_len := (others => '0');
end if;
sq2_trigger_r <= '0';
end if;
end if;
end if;
end process square2;
wave : process(clk, wav_enable, wav_playing, wav_volsh, wav_wav_r)
variable wav_fcnt : unsigned(10 downto 0);
variable wav_len : std_logic_vector(8 downto 0);
variable wav_shift_r : std_logic;
variable wav_shift : std_logic;
variable acc_fcnt : unsigned(11 downto 0);
variable wav_trigger_freq : std_logic_vector(10 downto 0);
begin
if wav_playing = '0' then
wav_wav <= (others => '0');
else
case wav_volsh is
when "01" => wav_wav <= wav_wav_r;
when "10" => wav_wav <= '0' & wav_wav_r(3 downto 1);
when "11" => wav_wav <= "00" & wav_wav_r(3 downto 2);
when others => wav_wav <= (others => '0');
end case;
end if;
if rising_edge(clk) then
if reset = '1' then
wav_wav_r <= SS_Sound3(49 downto 46); -- "0000";
wav_playing <= SS_Sound3( 50); -- '0';
wav_fcnt := (others => '0');
wav_shift_r := '0';
wav_index <= unsigned(SS_Sound3(55 downto 51)); -- (others => '0');
wav_access <= unsigned(SS_Sound3(57 downto 56)); -- (others => '0');
wav_len := (others => '0');
wav_trigger_r <= '0';
wav_trigger_freq := (others => '0');
elsif ce = '1' then
if wav_lenchange = '1' then
wav_len := wav_slen;
end if;
wav_trigger_r <= wav_trigger;
if snd_enable = '1' then
if wav_access > 0 then
wav_access <= wav_access - 1;
end if;
wav_shift := '0';
if en_snd2 = '1' then
-- Wave frequency timer Frequency = 4194304/(64*(2048-x)) Hz = 65536/(2048-x) Hz
if wav_playing = '1' then
acc_fcnt := ('0' & wav_fcnt) + to_unsigned(1, acc_fcnt'length);
if acc_fcnt(acc_fcnt'high) = '1' then
wav_shift := '1';
wav_fcnt := unsigned(wav_freq);
else
wav_fcnt := acc_fcnt(wav_fcnt'range);
end if;
end if;
end if;
if wav_trigger_r = '1' and wav_trigger = '0' then
wav_index <= (others => '0');
wav_shift_r := '0';
else
-- Rotate wave table on rising edge of wav_shift
if wav_shift = '1' and wav_shift_r = '0' then
wav_index <= wav_index + 1;
wav_wav_r <= wav_ram(to_integer(wav_index + 1));
wav_access <= "10";
end if;
wav_shift_r := wav_shift;
end if;
-- Length counter
if en_len = '1' or wav_lenquirk = '1' then
if wav_len > 0 and wav_lenchk = '1' then
wav_len := std_logic_vector(unsigned(wav_len) - 1);
end if;
end if;
if wav_playing = '1' then
-- Check for end of playing conditions
if (wav_lenchk = '1' and wav_len = 0) or wav_enable = '0' then
wav_playing <= '0';
end if;
end if;
if wav_trigger_r = '0' and wav_trigger = '1' then -- rising edge of trigger
wav_trigger_freq := wav_freq; -- keep copy of frequency to avoid change while delaying trigger
end if;
-- Check sample trigger and start playing
if wav_trigger_r = '1' and wav_trigger = '0' then
wav_fcnt := unsigned(wav_trigger_freq);
wav_playing <= '1';
if wav_len = 0 then -- trigger quirks
if wav_lenchk = '1' and en_len_r = '1' then
wav_len := "011111111"; -- 255
else
wav_len := "100000000"; -- 256
end if;
end if;
end if;
else
wav_wav_r <= "0000";
wav_playing <= '0';
wav_fcnt := (others => '0');
wav_shift_r := '0';
wav_index <= (others => '0');
wav_access <= (others => '0');
if is_gbc = '1' then
wav_len := (others => '0');
end if;
wav_trigger_r <= '0';
end if;
end if;
end if;
end process wave;
noise : process(clk, noi_vol, noi_svol, noi_envsgn)
variable noi_period : unsigned(19 downto 0); -- Noise period (calculated)
variable noi_fcnt : unsigned(19 downto 0);
variable noi_lfsr : unsigned(14 downto 0); -- 15 bits
variable noi_len : std_logic_vector(6 downto 0);
variable noi_envcnt : std_logic_vector(2 downto 0); -- Noise envelope timer count
variable noi_out : std_logic;
variable noi_xor : std_logic;
variable tmp_volume : unsigned(7 downto 0); -- used in zombie mode
begin
noi_dac_en <= '1';
if noi_svol & noi_envsgn = "00000" then
noi_dac_en <= '0';
end if;
if noi_out = '1' then
noi_wav <= noi_vol;
else
noi_wav <= "0000";
end if;
-- Sound processing
if rising_edge(clk) then
if reset = '1' then
noi_playing <= SS_Sound3( 58); -- '0';
noi_fcnt := (others => '0');
noi_lfsr := (others => '0');
noi_vol <= SS_Sound3(62 downto 59); -- "0000";
noi_envcnt := "000";
noi_out := '0';
noi_len := (others => '0');
noi_trigger_r <= '0';
elsif ce = '1' then
if noi_lenchange = '1' then
noi_len := noi_slen;
end if;
-- used to detect trigger negedge
noi_trigger_r <= noi_trigger;
if snd_enable = '0' then
noi_playing <= '0';
noi_fcnt := (others => '0');
noi_lfsr := (others => '0');
noi_vol <= "0000";
noi_envcnt := "000";
noi_out := '0';
if is_gbc = '1' then
noi_len := (others => '0');
end if;
noi_trigger_r <= '0';
else
-- LFSR
if noi_playing = '1' and en_snd4 = '1' then
if noi_fcnt = 1 then
-- Noise LFSR
noi_xor := not(noi_lfsr(0) xor noi_lfsr(1));
noi_lfsr := noi_xor & noi_lfsr(14 downto 1);
if noi_short = '1' then
noi_lfsr(6) := noi_xor;
end if;
noi_out := noi_lfsr(0);
noi_fcnt := noi_period;
else
noi_fcnt := noi_fcnt - 1;
end if;
end if;
-- Length counter
if (en_len = '1' or noi_lenquirk = '1') and noi_lenchk = '1' then
if noi_len > 0 then
noi_len := std_logic_vector(unsigned(noi_len) - 1);
end if;
end if;
-- Check for end of playing conditions
if noi_lenchk = '1' and noi_len = 0 then
noi_playing <= '0';
end if;
-- Envelope counter
if noi_playing = '1' and en_env = '1' and noi_envper /= "000" then
noi_envcnt := std_logic_vector(unsigned(noi_envcnt) - 1); -- decrement counter
if noi_envcnt = 0 then
if noi_envsgn = '1' then
if noi_vol /= "1111" then
noi_vol <= std_logic_vector(unsigned(noi_vol) + 1);
end if;
else
if noi_vol /= "0000" then
noi_vol <= std_logic_vector(unsigned(noi_vol) - 1);
end if;
end if;
-- reload counter with period
noi_envcnt := noi_envper;
end if;
end if;
-- Zombie mode
if ((noi_trigger = '0' and noi_trigger_r = '1') or noi_nr2change = '1') and noi_playing = '1' then
-- using sameboy's logic
tmp_volume := "0000" & unsigned(noi_vol);
if noi_envsgn = '1' then
tmp_volume := tmp_volume + 1;
end if;
if (noi_envsgn xor noi_envsgn_old) = '1' then
tmp_volume := X"10" - tmp_volume;
end if;
if (noi_envper /= "000") and (noi_envper_old = "000") and (tmp_volume /= "00000000") and (noi_envsgn = '0') then
tmp_volume := tmp_volume - 1;
end if;
if (noi_envper_old /= "000") and noi_envsgn = '1' then
tmp_volume := tmp_volume - 1;
end if;
noi_vol <= std_logic_vector(tmp_volume(3 downto 0));
end if;
-- Calculate noise period
if noi_trigger = '1' or noi_freqchange = '1' then
-- Calculate LFSR clock period from frequency formula:
-- 256 KiHz / (r * 2^S)
-- When r = 0, it is treated as 0.5 (i.e. 512 KiHz/2^S)
-- Here, the LFSR block frequency is 1 MiHz (en_snd4)
-- r = noi_div and S = noi_freqsh
-- First, set period to 4*r, or 2 if r == 0
noi_period := (others => '0');
noi_period(4 downto 2) := unsigned(noi_div);
if noi_div = "000" then
noi_period(1) := '1';
end if;
noi_period := noi_period sll to_integer(unsigned(noi_freqsh));
noi_fcnt := noi_period;
end if;
-- Check sample trigger and start playing
if noi_trigger_r = '1' and noi_trigger = '0' then -- falling edge of trigger
noi_playing <= '1';
noi_vol <= noi_svol;
noi_lfsr := (others => '0');
noi_envcnt := noi_envper;
if noi_len = 0 then -- trigger quirks
if noi_lenchk = '1' and en_len_r = '1' then
noi_len := "0111111"; -- 63
else
noi_len := "1000000"; -- 64
end if;
end if;
end if;
if noi_svol & noi_envsgn = "00000" then -- dac disabled, disable channel
noi_playing <= '0';
end if;
end if;
end if;
end if;
end process noise;
-- Analog hardware emulation
sq1_dac : apu_dac port map (clk=>clk, ce=>ce, dac_en=>sq1_dac_en, dac_invert => not remove_pops, dac_input=>sq1_wav,dac_output=>sq1_dac_out);
sq2_dac : apu_dac port map (clk=>clk, ce=>ce, dac_en=>sq2_dac_en, dac_invert => not remove_pops, dac_input=>sq2_wav,dac_output=>sq2_dac_out);
wav_dac : apu_dac port map (clk=>clk, ce=>ce, dac_en=>wav_enable, dac_invert => not remove_pops, dac_input=>wav_wav,dac_output=>wav_dac_out);
noi_dac : apu_dac port map (clk=>clk, ce=>ce, dac_en=>noi_dac_en, dac_invert => not remove_pops, dac_input=>noi_wav,dac_output=>noi_dac_out);
mixer : process (sq1_dac_out, sq2_dac_out, wav_dac_out, noi_dac_out, ch_map, ch_vol, remove_pops)
variable snd_left_in : signed(10 downto 0);
variable snd_right_in : signed(10 downto 0);
variable snd_tmp : signed(15 downto 0);
variable wav_analog : signed(8 downto 0);
begin
snd_left_in := (others => '0');
snd_right_in := (others => '0');
for k in 0 to 3 loop
case k is
when 0 =>
wav_analog := sq1_dac_out;
when 1 =>
wav_analog := sq2_dac_out;
when 2 =>
wav_analog := wav_dac_out;
when 3 =>
wav_analog := noi_dac_out;
when others => null;
end case;
if ch_map(k) = '1' then
snd_right_in := snd_right_in + wav_analog;
end if;
if ch_map(k + 4) = '1' then
snd_left_in := snd_left_in + wav_analog;
end if;
end loop;
snd_tmp := snd_right_in * signed(("00" & ch_vol(2 downto 0)) + '1');
if (remove_pops = '1') then
snd_right <= std_logic_vector(shift_left(snd_tmp,1)); -- Compensate lower volume
else
snd_right <= std_logic_vector(snd_tmp);
end if;
snd_tmp := snd_left_in * signed(("00" & ch_vol(6 downto 4)) + '1');
if (remove_pops = '1') then
snd_left <= std_logic_vector(shift_left(snd_tmp,1));
else
snd_left <= std_logic_vector(snd_tmp);
end if;
end process;
end SYN;
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity apu_dac is
port (
clk : in std_logic;
ce : in std_logic;
dac_en : in std_logic;
dac_invert : in std_logic;
dac_input : in std_logic_vector(3 downto 0);
dac_output : out signed(8 downto 0)
);
end apu_dac;
architecture apu_dac_arch of apu_dac is
-- Analog value has range [-256, 255], which will decay to zero when a DAC is disabled.
-- Sameboy uses a DAC decay speed tick of every 50 us, with 120 amplitude steps => Total decay in 6 ms.
-- For a 6 ms decay from max output (255), we want to tick the analog value down every ~100 clock cycles (f_clk = 4.19 MHz).
signal dac_decay_timer : integer range 0 to 100 := 0;
constant DAC_DECAY_PERIOD : integer := dac_decay_timer'high; -- Tick rate 41.5 kHz, full decay 6.1 ms
signal dac_analog : signed(8 downto 0);
-- Convert a DAC input code to a pseudo-analog value
function dac_out(
wav : std_logic_vector(3 downto 0);
invert : std_logic
) return signed is
begin
if (invert = '1') then
return signed((wav xor "0111") & "00000"); -- 0xF = -256, 0x0 = 224.
else
return signed("0" & wav & "0000"); -- 0xF = 240, 0x0 = 0.
end if;
end function;
begin
dac_output <= dac_analog;
timers : process(clk, ce, dac_en, dac_analog, dac_decay_timer)
begin
if rising_edge(clk) and ce = '1' then
if dac_en = '1' then
dac_decay_timer <= DAC_DECAY_PERIOD;
else
if dac_decay_timer > 0 then
dac_decay_timer <= dac_decay_timer - 1;
else
dac_decay_timer <= DAC_DECAY_PERIOD; -- Automatically reset timer while DAC disabled.
end if;
end if;
end if;
end process timers;
process(clk, ce, dac_en, dac_invert, dac_input, dac_decay_timer)
begin
if rising_edge(clk) and ce = '1' then
if dac_en = '1' then
dac_analog <= dac_out(dac_input, dac_invert);
elsif dac_decay_timer = 0 then
if dac_analog < 0 then
dac_analog <= dac_analog + 1;
elsif dac_analog > 0 then
dac_analog <= dac_analog - 1;
end if;
end if;
end if;
end process;
end apu_dac_arch;
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