diff --git a/lib/emac/src/piso.vhd b/lib/emac/src/piso.vhd new file mode 100644 index 0000000..fe05fa2 --- /dev/null +++ b/lib/emac/src/piso.vhd @@ -0,0 +1,90 @@ +LIBRARY IEEE; +USE IEEE.STD_LOGIC_1164.ALL; +USE IEEE.NUMERIC_STD.ALL; +use std.textio.all; -- Imports the standard textio package. + +use work.utils_pkg.all; -- Imports the standard textio package. + +ENTITY piso IS + Generic + ( + data_width_in : natural := 32; + data_width_out : natural := 8; + msb_first : boolean := false + ); + Port + ( + rst : in STD_LOGIC; + clk : in STD_LOGIC; + din_rdy : out STD_LOGIC; + din_vld : in STD_LOGIC; + din : in unsigned(data_width_in-1 downto 0); + dout_vld : out STD_LOGIC; + dout : out unsigned(data_width_out-1 downto 0) + + ); +END piso; + +ARCHITECTURE behavior OF piso IS + + constant num_shifts : natural := data_width_in/data_width_out; + signal pre_fin : STD_LOGIC; + signal rdy : STD_LOGIC; + signal shift_cnt_pipe : unsigned(num_shifts-2 downto 0); + signal shift_pipe : unsigned(data_width_in-1 downto 0); + +-------------------------------------------------------------------------- +begin + + pre_fin <= shift_cnt_pipe(shift_cnt_pipe'left-1); + + din_rdy <= rdy; + dout <= shift_pipe(shift_pipe'left downto shift_pipe'left-data_width_out+1) when msb_first + else shift_pipe(data_width_out-1 downto 0); + +-------------------------------------------------------------------------- +process(clk) +begin + if rising_edge(clk) then + if rst = '1' then + shift_cnt_pipe <= (others => '1'); + elsif rdy = '1' then + if din_vld = '1' then + shift_cnt_pipe <= (others => '0'); + shift_pipe <= din; + end if; + else + shift_cnt_pipe <= shift_cnt_pipe(shift_cnt_pipe'left-1 downto 0) & '1'; + if (msb_first) then + shift_pipe <= shift_pipe(shift_pipe'left-data_width_out downto 0) & (data_width_out-1 downto 0 => '0'); + else + shift_pipe <= (data_width_out-1 downto 0 => '0') & shift_pipe(shift_pipe'left downto data_width_out); + end if; + + end if; + end if; +end process; + +-------------------------------------------------------------------------- +process(clk) +begin + if rising_edge(clk) then + if rst = '1' then + rdy <= '0'; + dout_vld <= '0'; + elsif rdy = '1' then + if pre_fin = '1' then + dout_vld <= '0'; + if din_vld = '1' then + rdy <= '0'; + dout_vld <= '1'; + end if; + end if; + elsif pre_fin = '1' then + rdy <= '1'; + end if; + end if; +end process; + +-------------------------------------------------------------------------- +end behavior;