Subversion Repositories open8_urisc

-- Copyright (c)2023 Jeremy Seth Henry
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
--     * Redistributions of source code must retain the above copyright
--       notice, this list of conditions and the following disclaimer.
--     * Redistributions in binary form must reproduce the above copyright
--       notice, this list of conditions and the following disclaimer in the
--       documentation and/or other materials provided with the distribution,
--       where applicable (as part of a user interface, debugging port, etc.)
--
-- THIS SOFTWARE IS PROVIDED BY JEREMY SETH HENRY ``AS IS'' AND ANY
-- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-- DISCLAIMED. IN NO EVENT SHALL JEREMY SETH HENRY BE LIABLE FOR ANY
-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-- ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-- THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--
-- VHDL units : o8_mavg_8ch_16b_64d
-- Description: 8-channel moving average calculation for 16-bit unsigned data
--              Accumulator depth is 64 elements, using 1 block RAM.
--
-- Register Map:
-- Offset  Bitfield Description                        Read/Write
--   0x00  AAAAAAAA Raw Data (lower)                      (RW)
--   0x01  AAAAAAAA Raw Data (upper)                      (RW)
--   0x02  -----AAA Raw Channel Select                    (RW)
--   0x03  BA------ Update Accum & Int Enable / Busy      (RW*)
--   0x04  AAAAAAAA Avg Data (lower)                      (RW)
--   0x05  AAAAAAAA Avg Data (upper)                      (RW)
--   0x06  -----AAA Avg Channel Select                    (RW)
--   0x07  BA------ Flush Statistics & Int_Enable / Busy  (RW*)
--
-- Note: Writing bit A high will enable a CPU interrupt for the specified
--        operation. Writing a low will disable the interrupt. Bit B indicates
--        the operation status in either case.
 
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_misc.all;
 
library work;
  use work.open8_pkg.all;
 
entity o8_mavg_8ch_16b_64d is
generic(
  Autoflush_On_Reset         : boolean := TRUE;
  Address                    : ADDRESS_TYPE
);
port(
  Open8_Bus                  : in  OPEN8_BUS_TYPE;
  Write_Qual                 : in  std_logic := '1';
  Rd_Data                    : out DATA_TYPE;
  Interrupt                  : out std_logic
);
end entity;
 
architecture behave of o8_mavg_8ch_16b_64d is
 
  alias Clock                is Open8_Bus.Clock;
  alias Reset                is Open8_Bus.Reset;
 
  constant User_Addr         : std_logic_vector(15 downto 3)
                               := Address(15 downto 3);
  alias  Comp_Addr           is Open8_Bus.Address(15 downto 3);
  signal Addr_Match          : std_logic := '0';
 
  alias  Reg_Sel_d           is Open8_Bus.Address(2 downto 0);
  signal Reg_Sel_q           : std_logic_vector(2 downto 0) := "000";
  signal Wr_En_d             : std_logic := '0';
  signal Wr_En_q             : std_logic := '0';
  alias  Wr_Data_d           is Open8_Bus.Wr_Data;
  signal Wr_Data_q           : DATA_TYPE := x"00";
  signal Rd_En_d             : std_logic := '0';
  signal Rd_En_q             : std_logic := '0';
 
  signal RAW_Data            : std_logic_vector(15 downto 0) := (others => '0');
  alias  RAW_Data_L          is RAW_Data(7 downto 0);
  alias  RAW_Data_H          is RAW_Data(15 downto 8);
 
  signal RAW_Channel         : std_logic_vector(2 downto 0) := (others => '0');
 
  signal RAW_Valid           : std_logic := '0';
 
  signal Flush_Valid         : std_logic := '0';
  signal Flush_Busy          : std_logic := '0';
 
  type AVG_CTL_STATES is (IDLE,
                          RD_LAST, ADV_PTR, CALC_NEXT, WR_NEW, AVG_DONE,
                          FLUSH_INIT, FLUSH_RAM, FLUSH_DONE);
  signal AVG_Ctl             : AVG_CTL_STATES := FLUSH_INIT;
 
  signal Avg_Busy            : std_logic := '0';
 
  signal CH_Select           : std_logic_vector(2 downto 0) := (others => '0');
  signal Data_New            : std_logic_vector(15 downto 0) := (others => '0');
 
  signal RAM_Wr_Addr         : std_logic_vector(8 downto 0) := (others => '0');
  alias  RAM_Wr_Chan         is RAM_Wr_Addr(8 downto 6);
  alias  RAM_Wr_Ptr          is RAM_Wr_Addr(5 downto 0);
 
  signal RAM_Wr_Data         : std_logic_vector(15 downto 0) := (others => '0');
 
  signal RAM_Wr_En           : std_logic := '0';
 
  signal RAM_Rd_Addr         : std_logic_vector(8 downto 0) := (others => '0');
  alias  RAM_Rd_Chan         is RAM_Rd_Addr(8 downto 6);
  alias  RAM_Rd_Ptr          is RAM_Rd_Addr(5 downto 0);
 
  signal RAM_Rd_Data         : std_logic_vector(15 downto 0) := (others => '0');
  alias  Data_Old            is RAM_Rd_Data;
 
  type PTR_ARRAY is array (0 to 7) of std_logic_vector(5 downto 0);
  signal SP0_Pointers        : PTR_ARRAY;
  signal SPN_Pointers        : PTR_ARRAY;
 
  -- Accumulator width is bus_size (16) + log depth (6)
  type ACCUM_ARRAY is array (0 to 7) of unsigned(21 downto 0);
  signal Accumulators        : ACCUM_ARRAY;
 
  signal AVG_Channel         : std_logic_vector(2 downto 0) := (others => '0');
 
  signal AVG_Out             : std_logic_vector(15 downto 0) := (others => '0');
  alias AVG_Out_L            is AVG_Out(7 downto 0);
  alias AVG_Out_H            is AVG_Out(15 downto 8);
 
  signal AVG_Int_En          : std_logic := '0';
  signal Flush_Int_En        : std_logic := '0';
 
begin
 
  Addr_Match                 <= '1' when Comp_Addr = User_Addr else '0';
  Wr_En_d                    <= Addr_Match and Write_Qual and Open8_Bus.Wr_En;
  Rd_En_d                    <= Addr_Match and Open8_Bus.Rd_En;
 
  Register_IF_proc: process( Clock, Reset )
    variable i : integer := 0;
  begin
    if( Reset = Reset_Level )then
      Wr_En_q                <= '0';
      Wr_Data_q              <= x"00";
      Reg_Sel_q              <= (others => '0');
      Rd_En_q                <= '0';
      Rd_Data                <= OPEN8_NULLBUS;
 
      RAW_Data               <= (others => '0');
      RAW_Valid              <= '0';
      RAW_Channel            <= (others => '0');
 
      AVG_Out                <= (others => '0');
      AVG_Channel            <= (others => '0');
 
      AVG_Int_En             <= '0';
      Flush_Int_En           <= '0';
 
    elsif( rising_edge(Clock) )then
      Reg_Sel_q              <= Reg_Sel_d;
      Wr_En_q                <= Wr_En_d;
      Wr_Data_q              <= Wr_Data_d;
 
      Flush_Valid            <= '0';
      RAW_Valid              <= '0';
 
      if( Wr_En_q = '1' )then
        case( Reg_Sel_q )is
          when "000" =>
            RAW_Data_L       <= Wr_Data_q;
 
          when "001" =>
            RAW_Data_H       <= Wr_Data_q;
 
          when "010" =>
            RAW_Channel      <= Wr_Data_q(2 downto 0);
 
          when "011" =>
            AVG_Int_En       <= Wr_Data_q(6);
            RAW_Valid        <= not (Flush_Busy or Avg_Busy);
 
          when "110" =>
            AVG_Channel      <= Wr_Data_q(2 downto 0);
 
          when "111" =>
            Flush_Int_En     <= Wr_Data_q(6);
            Flush_Valid      <= not (Flush_Busy or Avg_Busy);
 
          when others =>
            null;
 
        end case;
      end if;
 
      i                      := conv_integer(AVG_Channel);
      AVG_Out                <= std_logic_vector(Accumulators(i)(21 downto 6));
 
      Rd_Data                <= OPEN8_NULLBUS;
      Rd_En_q                <= Rd_En_d;
      if( Rd_En_q = '1' )then
        case( Reg_Sel_q )is
          when "000" =>
            Rd_Data          <= RAW_Data_L;
 
          when "001" =>
            Rd_Data          <= RAW_Data_H;
 
          when "010" =>
            Rd_Data          <= "00000" & RAW_Channel;
 
          when "011" =>
            Rd_Data          <= Avg_Busy & AVG_Int_En & "000000";
 
          when "100" =>
            Rd_Data          <= AVG_Out_L;
 
          when "101" =>
            Rd_Data          <= AVG_Out_H;
 
          when "110" =>
            Rd_Data          <= "00000" & AVG_Channel;
 
          when "111" =>
            Rd_Data          <= Flush_Busy & Flush_Int_En & "000000";
 
          when others =>
            null;
 
        end case;
      end if;
 
    end if;
  end process;
 
  MAVG_Control_proc: process( Clock, Reset )
    variable i : integer := 0;
  begin
    if( Reset = Reset_Level )then
      AVG_Ctl                <= IDLE;
      if( Autoflush_On_Reset )then
        AVG_Ctl              <= FLUSH_INIT;
      end if;
 
      CH_Select              <= (others => '0');
      Data_New               <= (others => '0');
 
      Flush_Busy             <= '0';
      Avg_Busy               <= '0';
 
      for i in 0 to 7 loop
        SP0_Pointers(i)      <= (others => '1');
        SPN_Pointers(i)      <= (others => '0');
        Accumulators(i)      <= (others => '0');
      end loop;
 
      RAM_Wr_Addr            <= (others => '0');
      RAM_Wr_Data            <= (others => '0');
      RAM_Wr_En              <= '0';
      RAM_Rd_Addr            <= (others => '0');
 
      Interrupt              <= '0';
 
    elsif( rising_edge(Clock) )then
 
      Interrupt              <= '0';
 
      RAM_Wr_En              <= '0';
 
      Flush_Busy             <= '0';
      Avg_Busy               <= '0';
 
      i                      := conv_integer(unsigned(CH_Select));
 
      case( AVG_Ctl )is
        when IDLE =>
          if( Flush_Valid = '1' )then
            AVG_Ctl          <= FLUSH_INIT;
          elsif( RAW_Valid = '1' )then
            Data_New         <= RAW_Data;
            CH_Select        <= RAW_Channel;
            AVG_Ctl          <= RD_LAST;
          end if;
 
        -- Data Average Update States
        when RD_LAST =>
          Avg_Busy           <= '1';
          RAM_Rd_Chan        <= CH_Select;
          RAM_Rd_Ptr         <= SPN_Pointers(i);
          AVG_Ctl            <= ADV_PTR;
 
        when ADV_PTR =>
          Avg_Busy           <= '1';
          SP0_Pointers(i)    <= SP0_Pointers(i) + 1;
          AVG_Ctl            <= CALC_NEXT;
 
        when CALC_NEXT =>
          Avg_Busy           <= '1';
          Accumulators(i)    <= Accumulators(i) +
                                unsigned( Data_New ) -
                                unsigned( Data_Old );
          AVG_Ctl            <= WR_NEW;
 
        when WR_NEW =>
          Avg_Busy           <= '1';
          RAM_Wr_Chan        <= CH_Select;
          RAM_Wr_Ptr         <= SP0_Pointers(i);
          RAM_Wr_Data        <= Data_New;
          RAM_Wr_En          <= '1';
          SPN_Pointers(i)    <= SP0_Pointers(i) + 1;
          AVG_Ctl            <= AVG_DONE;
 
        when AVG_DONE =>
          Interrupt          <= AVG_Int_En;
          AVG_Ctl            <= IDLE;
 
        -- Buffer Flush States
        when FLUSH_INIT =>
          Flush_Busy         <= '1';
          RAM_Wr_Addr        <= (others => '0');
          RAM_Wr_Data        <= (others => '0');
          AVG_Ctl            <= FLUSH_RAM;
 
        when FLUSH_RAM =>
          Flush_Busy         <= '1';
          RAM_Wr_Addr        <= RAM_Wr_Addr + 1;
          RAM_Wr_En          <= '1';
          if( and_reduce(RAM_Wr_Addr) = '1' )then
            AVG_Ctl          <= FLUSH_DONE;
          end if;
 
        when FLUSH_DONE =>
          Interrupt          <= Flush_Int_En;
          AVG_Ctl            <= IDLE;
 
        when others =>
          null;
      end case;
 
    end if;
  end process;
 
  U_BUFF : entity work.mavg_buffer_16b
  port map(
    clock               => Clock,
    data                => RAM_Wr_Data,
    rdaddress           => RAM_Rd_Addr,
    wraddress           => RAM_Wr_Addr,
    wren                => RAM_Wr_En,
    q                   => RAM_Rd_Data
  );
 
end architecture;