Printer

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-- Ime i prezime:
-- Broj indeksa:
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library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.ALL;

entity Printer is port (
    iCLK        : in  std_logic;
    iRST        : in  std_logic;
    iPRINT      : in  std_logic;
    iADD_PAPER  : in  std_logic;
    iAMOUNT     : in  std_logic_vector(7 downto 0);
    oPRINT      : out std_logic;
    oERROR      : out std_logic
    );
end entity;

architecture Behavioral of Printer is
  signal sEMPTY : std_logic;
  signal sPAPER_EN : std_logic;
  signal sSLEEP_EN: std_logic;
  signal sSLEEP_TC: std_logic;
  signal sPRINT_EN: std_logic;
  signal sPRINT_TC: std_logic;
  signal sSLEEP_CNT : std_logic_vector(5 downto 0); -- modul 60
  signal sPRINT_CNT : std_logic_vector(3 downto 0); --modul 15
  signal sPAPER_CNT : std_logic_vector(7 downto 0);

  type state_type is (IDLE, SLEEP, CHECK_PAPER, PRINT, ERROR);
  signal state, state_next : state_type;
  ---

begin
    --registar stanja (asinhroni reset)
    process(iCLK,iRST) begin

        if(iRST ='1') then
            state <= IDLE;
        elsif(rising_edge(iCLK)) then
            state <= state_next;
        end if;
    end process;

    --automat
    process(state,state_next,iPRINT,sSLEEP_TC,sEMPTY,sPRINT_TC) begin

    case (state) is

    when IDLE =>
        if (iPRINT = '1') then
            state_next <= CHECK_PAPER;
        elsif(sSLEEP_TC = '1') then
            state_next <= SLEEP;
        else
            state_next <= IDLE;
        end if;

    when SLEEP =>
        if(iPRINT = '1') then
            state_next <= IDLE;
        else
            state_next <= SLEEP;
        end if;

    when CHECK_PAPER =>
        if(sEMPTY = '0') then
            state_next <= PRINT;
        elsif(sEMPTY = '1') then
            state_next <= ERROR;
        else
            state_next <= CHECK_PAPER;
        end if;

    when ERROR =>
        state_next <= IDLE;

    when PRINT =>
        if(sPRINT_TC = '1') then
            state_next <= IDLE;
        else
            state_next <= PRINT;
        end if;

    when others =>
        state_next <= IDLE;

    end case;

    end process;

    --funkcija izlaza automata

    oPRINT <= '1' when state = PRINT else '0';
    oERROR <= '1' when state = ERROR else '0';
    sSLEEP_EN <= '1' when state = IDLE else '0';
    sPRINT_EN <= '1' when state = PRINT else '0';
    sPAPER_EN <= '1' when state = CHECK_PAPER else '0';

    --brojac 1 (brojac za neaktivno stanje)
    process(iCLK,iRST) begin

        if(iRST = '1') then
            sSLEEP_CNT <= (others=>('0'));
            sSLEEP_TC <= '0';
        elsif(rising_edge(iCLK)) then
            if(sSLEEP_EN = '1') then
                if(sSLEEP_CNT = "111011") then -- 59 binarno
                    sSLEEP_CNT <= (others=>('0'));
                    sSLEEP_TC <= '1';
                else
                    sSLEEP_CNT <= sSLEEP_CNT +1;
                    sSLEEP_TC <= '0';
                end if;
            else
                sSLEEP_CNT <= (others=>('0'));
                sSLEEP_TC <= '0';
            end if;
        end if;
    end process;

    --brojac 2 (brojac za stampanje)
    process(iCLK,iRST) begin

        if(iRST = '1') then
            sPRINT_CNT <= (others=>('0'));
            sPRINT_TC <= '0';
        elsif(rising_edge(iCLK)) then
            if(sPRINT_EN = '1') then
                if(sPRINT_CNT = "1110") then -- 14 binarno
                    sPRINT_CNT <= "0000";
                    sPRINT_TC <= '1';
                else
                    sPRINT_CNT <= sPRINT_CNT +1;
                    sPRINT_TC <= '0';
                end if;
            else
                sPRINT_CNT <= "0000";
                sPRINT_TC <= '0';
            end if;
        end if;
    end process;


    --brojac 3(brojac za papir)
    process(iCLK,iRST) begin

        if(iRST = '1') then
            sPAPER_CNT <= (others=>('0')); --nisam siguran za ovo
            sEMPTY <= '1';
        elsif(rising_edge(iCLK)) then
            if(sPAPER_EN = '1') then
                if(iADD_PAPER = '1') then
                    sPAPER_CNT <= sPAPER_CNT + iAMOUNT;
                end if;

                if(sPAPER_CNT = "00000000") then
                    sEMPTY <= '1';
                else
                    sEMPTY <= '0';
                    sPAPER_CNT <= sPAPER_CNT - 1;
                end if;
            end if;
        end if;
    end process;

end Behavioral;