LAB 11: The Camera

Now all submodules must be merged into one design, the complete camera controller. So all modules have to be connected on a new level of hierarchy. This is called structural modelling. Structural modelling means the use (instantiation) and wiring of components resulting in a net list. VHDL provides the following means for structural modelling:

  • Component declaration
  • Component instantiation
  • Component configuration

Before you can use an object in VHDL you have to declare it. As in VHDL’87 only components can be instantiated these have to be declared first. This is done in the declarative part of an architecture or within a package which then has to be referenced.

The actual instantiation is the integration and wiring of the component. The component configuration determines which entity has to be used for a specific component instantiation. If the name of the component instantiated and the name of the entity to be used are identical (mandatory for synthesis!) then no specific component configuration has to be given.

The interface of the top module is shown in the following picture:

The interface of the top module

To do

  • Create the new VHDL file.
  • Write a testbench to verify the design. Use assertions to check the exposure times during the simulation run.
  • Compile and simulate the design.
  • Compare the number of Flip Flops that you would expect with the synthesis result.
CAMERA.VHD
library ieee;
use ieee.std_logic_1164.all;
use work.P_DISPLAY.all;
 
entity CAMERA is
  port(CLK         : in std_ulogic;
       RESET       : in std_ulogic;
       TRIGGER     : in std_ulogic;
       SWITCH      : in std_ulogic;
       KEYPAD      : in std_ulogic_vector(9 downto 0);
       MOTOR_READY : in std_ulogic;
       EXPOSE      : buffer std_ulogic;
       DISPLAY     : out T_DISPLAY);
end CAMERA;
 
architecture STRUCT of CAMERA is
  -- Camera components:
  -- DISP_DRV
  -- DECODER
  -- EXP_FF
  -- DISP_CTRL
  -- MOTOR_TIMER
  -- EXP_CTRL
  -- MAIN_CTRL
 
  -- All signals that are not present on the camera entity must be
  -- declared as internal signals
 
begin
  -- Instantiation of the components
  U_DECODER : DECODER
    port map(
      KEYPAD => KEYPAD,
      KEY    => W_KEY);
end STRUCT;
 
configuration CFG_CAMERA of CAMERA is
  for STRUCT
    -- The case-based architecture shall be selected for the DECODER
  end for;
end CFG_CAMERA;

LAB 4, 5, 6, 7, 8, 9, 10, 11

P_DISPLAY.VHD
library ieee;
use ieee.std_logic_1164.all;
 
package P_DISPLAY is
  type T_DIGITS  is array (2 downto 0) of integer range 0 to 10;
  type T_DISPLAY is array (2 downto 0) of std_ulogic_vector(6 downto 0);
 
  constant SEG_0 : std_ulogic_vector(6 downto 0):= "0111111";
  constant SEG_1 : std_ulogic_vector(6 downto 0):= "0000011";
  constant SEG_2 : std_ulogic_vector(6 downto 0):= "1101101";
  constant SEG_3 : std_ulogic_vector(6 downto 0):= "1100111";
  constant SEG_4 : std_ulogic_vector(6 downto 0):= "1010011";
  constant SEG_5 : std_ulogic_vector(6 downto 0):= "1110110";
  constant SEG_6 : std_ulogic_vector(6 downto 0):= "1111110";
  constant SEG_7 : std_ulogic_vector(6 downto 0):= "0100011";
  constant SEG_8 : std_ulogic_vector(6 downto 0):= "1111111";
  constant SEG_9 : std_ulogic_vector(6 downto 0):= "1110111";
  constant SEG_E : std_ulogic_vector(6 downto 0):= "1111100";
 
  -- pragma translate_off
  procedure DISPLAY_DIGIT(signal DISPLAY:T_DISPLAY);
  -- pragma translate_on
end P_DISPLAY;
 
-- pragma translate_off
use std.textio.all;
package body P_DISPLAY is
  ------------------------------
  --
  --            111111111112222
  --   123456789012345678901234
  --  1  #5##    ####    ####
  --  2 #    #  #    #  #    #
  --  3 4    0  #    #  #    #
  --  4 #    #  #    #  #    #
  --  5  #6##    ####    ####
  --  6 #    #  #    #  #    #
  --  7 3    1  #    #  #    #
  --  8 #    #  #    #  #    #
  --  9  #2##    ####    ####
  --
  ------------------------------
 
  constant ACTIVE_SEG: character := '#';
  constant EMPTY_SEG:  character := ' ';
 
  -- Width and height of a digit
  constant WIDTH:  integer := 8;
  constant HEIGHT: integer := 9;
 
  -- Datatypes to store the complete display in a matrix
  subtype T_MATRIX_ROW  is bit_vector (1 to 3*WIDTH);
  type    T_DISP_MATRIX is array (1 to HEIGHT) of T_MATRIX_ROW;
 
  -- Definition of the appearance of the 6 segments
  subtype T_DIGIT_ROW is bit_vector(1 to WIDTH);
  type    T_SEG_DEF   is array (1 to HEIGHT) of T_DIGIT_ROW;
  type    T_DIGIT_DEF is array (0 to 6) of T_SEG_DEF;
  constant DIGIT_DEF: T_DIGIT_DEF :=(("00000000", --   ....
                                      "00000010", --  .    #
                                      "00000010", --  .    0
                                      "00000010", --  .    #
                                      "00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000"),--   ....
 
                                     ("00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --   ....
                                      "00000010", --  .    #
                                      "00000010", --  .    1
                                      "00000010", --  .    #
                                      "00000000"),--   ....
 
                                     ("00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00111100"),--   #2##
 
                                     ("00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --   ....
                                      "01000000", --  #    .
                                      "01000000", --  3    .
                                      "01000000", --  #    .
                                      "00000000"),--   ....
 
                                     ("00000000", --   ....
                                      "01000000", --  #    .
                                      "01000000", --  4    .
                                      "01000000", --  #    .
                                      "00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000"),--   ....
 
                                     ("00111100", --   #5##
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000"),--   ....
 
                                     ("00000000", --   ....
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00111100", --   #6##
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000", --  .    .
                                      "00000000"));--  ....
 
  procedure DISPLAY_DIGIT(signal DISPLAY:T_DISPLAY) is
    file OUTFILE : TEXT is out "display.txt";
 
    variable L : line;
    variable DISP_TEXT: string(T_MATRIX_ROW'range);
 
    variable DISP_MATRIX: T_DISP_MATRIX;
    variable COL_L: integer;
    variable COL_R: integer;
 
  begin
    -- Clear the display
    DISP_MATRIX := (others => (others => '0'));
 
    -- Loop over all digits
    for DIGIT in T_DISPLAY'range loop
      -- Calculate the left- and rightmost columns
      COL_L := DIGIT*WIDTH + 1;
      COL_R := DIGIT*WIDTH + WIDTH;
 
      -- Loop over all segments
      for SEGMENT in 0 to 6 loop
        if DISPLAY(DIGIT)(SEGMENT) = '1' then
          -- Copy the matrix to the final display
          -- Loop over all rows of the display
          for ROW in T_SEG_DEF'range loop
            DISP_MATRIX(ROW)(COL_L to COL_R) :=
              DISP_MATRIX(ROW)(COL_L to COL_R) or
              DIGIT_DEF(SEGMENT)(ROW);
          end loop;
        end if;
      end loop;
    end loop;
 
    -- Write the matrix to a textfile
    for I in T_DISP_MATRIX'range loop
      -- Start with an empty line
      DISP_TEXT := (others => EMPTY_SEG);
 
      for J in T_MATRIX_ROW'range loop
        if DISP_MATRIX(I)(J) = '1' then
          DISP_TEXT(J) := ACTIVE_SEG;
        end if;
      end loop;
 
      -- Write the line
      write(L, DISP_TEXT);
      writeline(OUTFILE, L);
    end loop;
 
  end DISPLAY_DIGIT;
end P_DISPLAY;
-- pragma translate_on