Курсовая работа: Синтез схеми ПЛІС для інвертора

address: OUT STD_LOGIC_VECTOR (6 DOWNTO 0); -- external RAM address

data: INOUT STD_LOGIC_VECTOR (7 DOWNTO 0); -- system bus

web: OUT STD_LOGIC; -- external RAM active-low write-enable

oeb: OUT STD_LOGIC; -- external RAM active-low output-enable

sel_ram: out std_logic;

carry_out : out std_logic;

pc_out: OUT STD_LOGIC_VECTOR (6 DOWNTO 0);

ir_out: out std_logic_vector (7 downto 0);

acc_out: out std_logic_vector (3 downto 0));

END gnome;

-- GNOME processor architecture behavioral description

ARCHITECTURE gnome_arch OF gnome IS

-- current and next GNOME state-machine state

SIGNAL curr_st, next_st: STD_LOGIC_VECTOR (1 DOWNTO 0);

-- possible GNOME state-machine states and their definitions

CONSTANT FETCH: STD_LOGIC_VECTOR (1 DOWNTO 0) := "00"; -- fetch instruction

CONSTANT DECODE: STD_LOGIC_VECTOR (1 DOWNTO 0) := "01"; -- decode

CONSTANT EXECUTE: STD_LOGIC_VECTOR (1 DOWNTO 0) := "11"; -- execute

-- current and next program counter value

SIGNAL curr_pc, next_pc: STD_LOGIC_VECTOR (6 DOWNTO 0);

-- current and next accumulator value

SIGNAL curr_acc, next_acc: STD_LOGIC_VECTOR (3 DOWNTO 0);

-- current and next carry flag value

SIGNAL curr_carry, next_carry: STD_LOGIC;

-- current and next zero flag value

SIGNAL curr_zero, next_zero: STD_LOGIC;

-- sum vector for holding adder output

SIGNAL sum: STD_LOGIC_VECTOR (4 DOWNTO 0);

SIGNAL read: STD_LOGIC; -- 1 when reading RAM