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-- Converted from AHBMASTER_FIC.v

-- AHBMASTER_FIC.v

--`timescale 1 ns / 100 ps

-------------------------------------------------------------------------------

-- Title      : Custom AHB master

-------------------------------------------------------------------------------

-- File       : AHBMASTER_FIC.vhd

-- Author     : uson

-- Company    : 

-- Device     : microsemi FPGA

-- Standard   : VHDL

-- Special Notes: This is code is for refernce only. You shouldn't use it in real 

-- design as it is

-------------------------------------------------------------------------------

-- Description:

-- This code creates an AHB-Lite master wrapper to FIC 

-- The AHB interface to Logic will initaite AMBA transaction by sending write/read signals.

-------------------------------------------------------------------------------

-- Revisions  : V1.0 

-------------------------------------------------------------------------------*/

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_arith.all;

use ieee.std_logic_unsigned.all;

entity AHBMASTER_FIC is

        port (

                HCLK    : in  std_logic;

                HRESETn : in  std_logic;

        --AHB interface to Logic

                LREAD   : in  std_logic;

                LWRITE  : in  std_logic;

                ADDR    : in  std_logic_vector(31 downto 0);

                DATAIN  : in  std_logic_vector(31 downto 0);

                DATAOUT : out std_logic_vector(31 downto 0);

        -- AHB Side Interfacing with FIC 

                HADDR   : out std_logic_vector(31 downto 0);

                HTRANS  : out std_logic_vector(1 downto 0);

                HWRITE  : out std_logic;

                HSIZE   : out std_logic_vector(2 downto 0);

                HBURST  : out std_logic_vector(2 downto 0);

                HPROT   : out std_logic_vector(3 downto 0);

                HWDATA  : out std_logic_vector(31 downto 0);

                HRDATA  : in  std_logic_vector(31 downto 0);

                HREADY  : in  std_logic;

                HRESP   : in  std_logic_vector(1 downto 0);

                RESP_err        : out std_logic_vector(1 downto 0);

                ahb_busy        : out std_logic

        );

end AHBMASTER_FIC;

architecture RTL of AHBMASTER_FIC is

        -- AHB FSM States

        signal ahb_fsm_current_state    : std_logic_vector(2 downto 0);

        constant Idle   : std_logic_vector(2 downto 0) := "000";

        constant Write_FIC_0    : std_logic_vector(2 downto 0) := "001";

        constant Write_FIC_1    : std_logic_vector(2 downto 0) := "010";

        constant Write_FIC_2    : std_logic_vector(2 downto 0) := "011";

        constant Read_FIC_0     : std_logic_vector(2 downto 0) := "100";

        constant Read_FIC_1     : std_logic_vector(2 downto 0) := "101";

        constant Read_FIC_2     : std_logic_vector(2 downto 0) := "110";

        signal HADDR_int        : std_logic_vector(31 downto 0); --temporary hold the address

        signal HWDATA_int       : std_logic_vector(31 downto 0); --temporary hold the data

        signal HSIZE_int        : std_logic_vector(2 downto 0);

        -- since the current coreahblite is 32 bit, we are using Hsize=10 (32-bit), but can be changed

-- WARNING(5) in line 54: Please write a signal width part in the following sentence, manually.

        constant Data_size      : std_logic_vector(7 downto 0) := x"20"; -- 32

begin

        RESP_err    <= HRESP;

        HBURST      <= "000";

        HPROT       <= "0011";

        HSIZE_int       <= "010";

--generate

--    if (Data_size == 32) begin

--        assign HSIZE_int  = 2'b10;

--    end

--    else if (Data_size == 16) begin

--        assign HSIZE_int  = 2'b01;

--    end

--    else if (Data_size ==  8) begin

--        assign HSIZE_int  = 2'b00;

--    end

--endgenerate

        -- FSM That Acts as Master on AHB Bus

        -- Assuming only Non-Sequential & Idle

        v2v_pr_0:process (HCLK, HRESETn)

        begin

                if (HRESETn = '0') then

                        HADDR   <= x"00000000";

                        HTRANS  <= "00";                        --Idle

                        HWRITE  <= '0';

                        HSIZE   <= "010";                       -- 32 Bit Mode

                        HWDATA  <= x"00000000";

                        DATAOUT <= x"00000000";

                        ahb_fsm_current_state   <= Idle;

                        ahb_busy        <= '0';

                elsif (HCLK'event and HCLK = '1') then

                        case (ahb_fsm_current_state) is

                        when Idle =>

                        --0x00

                                if (LWRITE = '1') then

                                        ahb_fsm_current_state   <= Write_FIC_0;

                                        HADDR   <= ADDR;

                                        HADDR_int       <= ADDR;

                                        HWDATA_int      <= DATAIN;

                                        ahb_busy        <= '1';

                                elsif (LREAD = '1') then

                                        ahb_fsm_current_state   <= Read_FIC_0;

                                        HADDR   <= ADDR;

                                        HADDR_int       <= ADDR;

                                        ahb_busy        <= '1';

                                else

                                        ahb_fsm_current_state   <= Idle;

                                end if;

                        when Write_FIC_0 =>

                        --0x01  store the address+control signals and apply to coreahblite

                                HTRANS  <= "10";

                                HSIZE   <= HSIZE_int;

                                HWRITE  <= '1';

                                ahb_fsm_current_state   <= Write_FIC_1;

                                ahb_busy        <= '1';

                        when Write_FIC_1 =>

                        --0x02 

                                if (HREADY = '0') then                                   --keep the address+control signals when slave is not ready yet

                                        HTRANS  <= "10";

                                        HSIZE   <= HSIZE_int;

                                        HWRITE  <= '1';

                                        HADDR   <= HADDR_int;

                                        ahb_fsm_current_state   <= Write_FIC_1;

                                        ahb_busy        <= '1';

                                else

                                        HWDATA  <= HWDATA_int;                                  --send the data+go to next state, doesn't need to keep the address+other controls active

                                        HADDR   <= x"00000000";

                                        HTRANS  <= "00";

                                        HWRITE  <= '0';

                                        ahb_fsm_current_state   <= Write_FIC_2;

                                        ahb_busy        <= '1';

                                end if;

                        when Write_FIC_2 =>

                        --0x03

                                if (HREADY = '0') then                                   --keep the data when slave is not ready yet

                                        ahb_fsm_current_state   <= Write_FIC_2;

                                        ahb_busy        <= '1';

                                else

                                        ahb_fsm_current_state   <= Idle;                --finish the write transfer  

                                        ahb_busy        <= '0';

                                end if;

                        when Read_FIC_0 =>

                        --0x04 store the address+control signals and apply to coreahblite

                                HTRANS  <= "10";

                                HSIZE   <= HSIZE_int;

                                HWRITE  <= '0';

                                ahb_fsm_current_state   <= Read_FIC_1;

                                ahb_busy        <= '1';

                        when Read_FIC_1 =>

                        --0x05

                                if (HREADY = '1') then                                  -- go to next state

                                        ahb_fsm_current_state   <= Read_FIC_2;

                                else

                                        HTRANS  <= "10";                                            --keep the address+control signals when slave is not ready yet

                                        HSIZE   <= HSIZE_int;

                                        HWRITE  <= '0';

                                        HADDR   <= HADDR_int;

                                        ahb_fsm_current_state   <= Read_FIC_1;

                                        ahb_busy        <= '1';

                                end if;

                        when Read_FIC_2 =>

                        --0x06                         

                                if (HREADY = '1') then                                  --read the data+finish the read transfer 

                                        DATAOUT <= HRDATA;

                                        ahb_fsm_current_state   <= Idle;

                                        ahb_busy        <= '0';

                                else

                                        ahb_fsm_current_state   <= Read_FIC_2;  --waiting slave to be ready

                                        ahb_busy        <= '1';

                                end if;

                                HADDR   <= x"00000000";                                 --doesn't need to keep the address+other controls any more

                                HTRANS  <= "00";

                        end case;

                end if;

        end process;

end RTL;