دفتر فنی مهندسی آموزه های هزاره سوم

entity ds18b20_ctrl is

    port

    (

        clk                : IN std_logic;    -- 100mhz

--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--

        temp_sensor_id     : OUT std_logic_vector(63 downto 0); -- Unique Serial Code       

        -- The default resolution at power-up is 12-bit.

        temperature        : OUT std_logic_vector(15 downto 0); -- -55°C to +125°C       

        -- The DS18B20 output temperature data is calibrated in degrees Celsius;

        -- for Fahrenheit applications, a lookup table or conversion routine must

        -- be used.

        -- output * 0.0625 = output / 16 = temperature(11 downto 4)

--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--        

        temp_sensor_dq     : INOUT std_logic := 'Z' -- 1-Wire Digital Thermometer

    );

end ds18b20_ctrl;

--==============================================================================--

architecture Behavioral of ds18b20_ctrl is

--==============================================================================--

-- Constant Declarations 

    constant MAX_TPDTCT            : integer := 100000; -- 1ms   

    constant MAX_TSTART            : integer := 50000; -- 500us 

-- PARAMETER                    SYMBOL      MIN        MAX        UNITS

-- Temperature Conversion Time  tCONV                  750        ms

-- Time to Strong Pull-up On    tSPON                  10         us

-- Time Slot                    tSLOT                  120        us

-- Recovery Time                tREC        1                     us

-- Write 0 Low Time             tLOW0       60         120        us

-- Write 1 Low Time             tLOW1       1          15         us

-- Read Data Valid              tRDV                   15         us

-- Reset Time High              tRSTH       480                   us

-- Reset Time Low               tRSTL       480                   us

-- Presence-Detect High         tPDHIGH     15         60         us

-- Presence-Detect Low          tPDLOW      60         240        us 

    constant MAX_TPDLOW      : integer := 24100;

    constant MIN_TPDLOW      : integer := 5900;       

    constant MIN_TRSTL0      : integer := 55000;

    constant MIN_TRSTL1      : integer := 54000; -- MIN_TRSTL0 - 10us   

    constant MIN_TLOW0       : integer := 6500;

    constant MIN_TLOW1       : integer := 500; 

-- All write time slots must be a minimum of 60us in duration with a minimum of

-- a 1us recovery time between individual write slots.

    constant MIN_TWSLOT      : integer := 9500;

-- All read time slots must be a minimum of 60us in duration with a minimum of

-- a 1us recovery time between slots.   

    constant MIN_TRSLOT      : integer := 7000; 

-- Recovery Time: tREC > 1us    

    constant MIN_TREC        : integer := 200;   

-- Read Data Valid: tRDV < 15us

    constant MAX_TRDV        : integer := 1200;   

    constant MAX_TBSCMD      : integer := 59000; 

-- Temperature Conversion Time: tCONV < 750ms

    constant MAX_TCONV       : integer := 76000000;

...