| Line 50... |
Line 50... |
-- control --
|
-- control --
|
clk_i : in std_ulogic; -- clock, rising edge
|
clk_i : in std_ulogic; -- clock, rising edge
|
rstn_i : in std_ulogic; -- async reset, low-active
|
rstn_i : in std_ulogic; -- async reset, low-active
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clear_i : in std_ulogic; -- sync reset, high-active
|
clear_i : in std_ulogic; -- sync reset, high-active
|
level_o : out std_ulogic_vector(index_size_f(FIFO_DEPTH) downto 0); -- fill level
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level_o : out std_ulogic_vector(index_size_f(FIFO_DEPTH) downto 0); -- fill level
|
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half_o : out std_ulogic; -- FIFO is at least half full
|
-- write port --
|
-- write port --
|
wdata_i : in std_ulogic_vector(FIFO_WIDTH-1 downto 0); -- write data
|
wdata_i : in std_ulogic_vector(FIFO_WIDTH-1 downto 0); -- write data
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we_i : in std_ulogic; -- write enable
|
we_i : in std_ulogic; -- write enable
|
free_o : out std_ulogic; -- at least one entry is free when set
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free_o : out std_ulogic; -- at least one entry is free when set
|
-- read port --
|
-- read port --
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| Line 81... |
Line 82... |
free : std_ulogic;
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free : std_ulogic;
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avail : std_ulogic;
|
avail : std_ulogic;
|
end record;
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end record;
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signal fifo : fifo_t;
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signal fifo : fifo_t;
|
|
|
|
signal level_diff : std_ulogic_vector(index_size_f(FIFO_DEPTH) downto 0);
|
|
|
begin
|
begin
|
|
|
-- Sanity Checks --------------------------------------------------------------------------
|
-- Sanity Checks --------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
assert not (FIFO_DEPTH = 0) report "NEORV32 CONFIG ERROR: FIFO depth has to be > 0." severity error;
|
assert not (FIFO_DEPTH = 0) report "NEORV32 CONFIG ERROR: FIFO depth has to be > 0." severity error;
|
assert not (is_power_of_two_f(FIFO_DEPTH) = false) report "NEORV32 CONFIG ERROR: FIFO depth has to be a power of two." severity error;
|
assert not (is_power_of_two_f(FIFO_DEPTH) = false) report "NEORV32 CONFIG ERROR: FIFO depth has to be a power of two." severity error;
|
|
|
|
|
-- Access Control -------------------------------------------------------------------------
|
-- Access Control -------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
fifo.re <= re_i when (FIFO_SAFE = false) else (re_i and fifo.avail);
|
fifo.re <= re_i when (FIFO_SAFE = false) else (re_i and fifo.avail); -- read only if data available
|
fifo.we <= we_i when (FIFO_SAFE = false) else (we_i and fifo.free);
|
fifo.we <= we_i when (FIFO_SAFE = false) else (we_i and fifo.free); -- write only if space left
|
|
|
|
|
-- FIFO Control ---------------------------------------------------------------------------
|
-- FIFO Control ---------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
fifo_control: process(rstn_i, clk_i)
|
fifo_control: process(rstn_i, clk_i)
|
| Line 124... |
Line 127... |
fifo.match <= '1' when (fifo.r_pnt(fifo.r_pnt'left-1 downto 0) = fifo.w_pnt(fifo.w_pnt'left-1 downto 0)) or (FIFO_DEPTH = 1) else '0';
|
fifo.match <= '1' when (fifo.r_pnt(fifo.r_pnt'left-1 downto 0) = fifo.w_pnt(fifo.w_pnt'left-1 downto 0)) or (FIFO_DEPTH = 1) else '0';
|
fifo.full <= '1' when (fifo.r_pnt(fifo.r_pnt'left) /= fifo.w_pnt(fifo.w_pnt'left)) and (fifo.match = '1') else '0';
|
fifo.full <= '1' when (fifo.r_pnt(fifo.r_pnt'left) /= fifo.w_pnt(fifo.w_pnt'left)) and (fifo.match = '1') else '0';
|
fifo.empty <= '1' when (fifo.r_pnt(fifo.r_pnt'left) = fifo.w_pnt(fifo.w_pnt'left)) and (fifo.match = '1') else '0';
|
fifo.empty <= '1' when (fifo.r_pnt(fifo.r_pnt'left) = fifo.w_pnt(fifo.w_pnt'left)) and (fifo.match = '1') else '0';
|
fifo.free <= not fifo.full;
|
fifo.free <= not fifo.full;
|
fifo.avail <= not fifo.empty;
|
fifo.avail <= not fifo.empty;
|
fifo.level <= std_ulogic_vector(to_unsigned(FIFO_DEPTH, fifo.level'length)) when (fifo.full = '1') else std_ulogic_vector(unsigned(fifo.w_pnt) - unsigned(fifo.r_pnt));
|
level_diff <= std_ulogic_vector(unsigned(fifo.w_pnt) - unsigned(fifo.r_pnt));
|
|
fifo.level <= std_ulogic_vector(to_unsigned(FIFO_DEPTH, fifo.level'length)) when (fifo.full = '1') else level_diff;
|
|
|
-- status output --
|
-- status output --
|
level_o <= fifo.level;
|
level_o <= fifo.level;
|
free_o <= fifo.free;
|
free_o <= fifo.free;
|
avail_o <= fifo.avail;
|
avail_o <= fifo.avail;
|
|
|
|
fifo_half_level:
|
|
if (FIFO_DEPTH > 1) generate
|
|
half_o <= level_diff(level_diff'left-1) or fifo.full;
|
|
end generate;
|
|
|
|
fifo_half_level_simple:
|
|
if (FIFO_DEPTH = 1) generate
|
|
half_o <= fifo.full;
|
|
end generate;
|
|
|
|
|
-- FIFO Memory ----------------------------------------------------------------------------
|
-- FIFO Memory ----------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
-- -------------------------------------------------------------------------------------------
|
fifo_memory_write: process(clk_i)
|
fifo_memory_write: process(clk_i)
|
begin
|
begin
|
| Line 159... |
Line 173... |
fifo_read_sync:
|
fifo_read_sync:
|
if (FIFO_RSYNC = true) generate
|
if (FIFO_RSYNC = true) generate
|
fifo_memory_read: process(clk_i)
|
fifo_memory_read: process(clk_i)
|
begin
|
begin
|
if rising_edge(clk_i) then
|
if rising_edge(clk_i) then
|
if (fifo.re = '1') then
|
|
if (FIFO_DEPTH = 1) then
|
if (FIFO_DEPTH = 1) then
|
rdata_o <= fifo.datas;
|
rdata_o <= fifo.datas;
|
else
|
else
|
rdata_o <= fifo.data(to_integer(unsigned(fifo.r_pnt(fifo.r_pnt'left-1 downto 0))));
|
rdata_o <= fifo.data(to_integer(unsigned(fifo.r_pnt(fifo.r_pnt'left-1 downto 0))));
|
end if;
|
end if;
|
end if;
|
end if;
|
end if;
|
|
end process fifo_memory_read;
|
end process fifo_memory_read;
|
end generate;
|
end generate;
|
|
|
|
|
end neorv32_fifo_rtl;
|
end neorv32_fifo_rtl;
|
