各种功能计数器.txt

FPGA里面的计数器相关资料及程序汇总大全

各种功能的计数器 vhdl


Library IEEE ;
use IEEE.std_logic_1164.all ;
use IEEE.std_logic_arith.all ;

ENTITY counters IS

PORT
(
d : IN INTEGER RANGE 0 TO 255;
clk : IN BIT;
clear : IN BIT;
ld : IN BIT;
enable : IN BIT;
up_down : IN BIT;
qa : OUT INTEGER RANGE 0 TO 255;
qb : OUT INTEGER RANGE 0 TO 255;
qc : OUT INTEGER RANGE 0 TO 255;
qd : OUT INTEGER RANGE 0 TO 255;
qe : OUT INTEGER RANGE 0 TO 255;
qf : OUT INTEGER RANGE 0 TO 255;
qg : OUT INTEGER RANGE 0 TO 255;
qh : OUT INTEGER RANGE 0 TO 255;
qi : OUT INTEGER RANGE 0 TO 255;
qj : OUT INTEGER RANGE 0 TO 255;
qk : OUT INTEGER RANGE 0 TO 255;
ql : OUT INTEGER RANGE 0 TO 255;
qm : OUT INTEGER RANGE 0 TO 255;
qn : OUT INTEGER RANGE 0 TO 255
);

END counters;

ARCHITECTURE a OF counters IS
BEGIN
-- An enable counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF enable = '1' THEN
cnt := cnt + 1;
END IF;
END IF;

qa <= cnt;

END PROCESS;

-- A synchronous load counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF ld = '0' THEN
cnt := d;
ELSE
cnt := cnt + 1;
END IF;
END IF;

qb <= cnt;
END PROCESS;

-- A synchronous clear counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
cnt := cnt + 1;
END IF;
END IF;

qc <= cnt;

END PROCESS;

-- An up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
cnt := cnt + direction;
END IF;

qd <= cnt;

END PROCESS;

-- A synchronous load enable counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF ld = '0' THEN
cnt := d;
ELSE
IF enable = '1' THEN
cnt := cnt + 1;
END IF;
END IF;
END IF;

qe <= cnt;

END PROCESS;

-- An enable up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
IF enable = '1' THEN
cnt := cnt + direction;
END IF;
END IF;

qf <= cnt;

END PROCESS;

-- A synchronous clear enable counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
IF enable = '1' THEN
cnt := cnt + 1;
END IF;
END IF;
END IF;

qg <= cnt;

END PROCESS;

-- A synchronous load clear counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
IF ld = '0' THEN
cnt := d;
ELSE
cnt := cnt + 1;
END IF;
END IF;
END IF;

qh <= cnt;

END PROCESS;

-- A synchronous load up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
IF ld = '0' THEN
cnt := d;
ELSE
cnt := cnt + direction;
END IF;
END IF;

qi <= cnt;

END PROCESS;

-- A synchronous load enable up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
IF ld = '0' THEN
cnt := d;
ELSE
IF enable = '1' THEN
cnt := cnt + direction;
END IF;
END IF;
END IF;

qj <= cnt;

END PROCESS;

-- A synchronous clear load enable counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
IF ld = '0' THEN
cnt := d;
ELSE
IF enable = '1' THEN
cnt := cnt + 1;
END IF;
END IF;
END IF;
END IF;

qk <= cnt;

END PROCESS;

-- A synchronous clear up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
cnt := cnt + direction;
END IF;
END IF;

ql <= cnt;

END PROCESS;

-- A synchronous clear enable up/down counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
VARIABLE direction : INTEGER;
BEGIN
IF (up_down = '1') THEN
direction := 1;
ELSE
direction := -1;
END IF;

IF (clk'EVENT AND clk = '1') THEN
IF clear = '0' THEN
cnt := 0;
ELSE
IF enable = '1' THEN
cnt := cnt + direction;
END IF;
END IF;
END IF;

qm <= cnt;

END PROCESS;

-- A modulus 200 up counter
PROCESS (clk)
VARIABLE cnt : INTEGER RANGE 0 TO 255;
CONSTANT modulus : INTEGER := 200;
BEGIN
IF (clk'EVENT AND clk = '1') THEN
IF cnt = modulus THEN
cnt := 0;
ELSE
cnt := cnt + 1;
END IF;
END IF;

qn <= cnt;

END PROCESS;
END a;