alarm_counter.vhd

本文件是针对了解闹钟控制系统而写的一个VHDL源代码。

--时间计数器的源程序ALARM_COUNTER.VHD
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE WORK.P_ALARM.ALL;
ENTITY ALARM_COUNTER IS
   PORT(NEW_CURRENT_TIME:IN  T_CLOCK_TIME;
    LOAD_NEW_C:IN  STD_LOGIC;
    CLK:IN  STD_LOGIC;
    RESET:IN  STD_LOGIC;
    CURRENT_TIME:OUT T_CLOCK_TIME);
END ENTITY ALARM_COUNTER;

ARCHITECTURE ART OF ALARM_COUNTER IS
    SIGNAL I_CURRENT_TIME: T_CLOCK_TIME;
  BEGIN
  PROCESS(CLK,RESET,LOAD_NEW_C) IS
  VARIABLE  C_T:T_CLOCK_TIME;
  BEGIN
  IF RESET = '1' THEN
     I_CURRENT_TIME<= (0,0,0,0);
  ELSIF LOAD_NEW_C ='1' THEN
     I_CURRENT_TIME <= NEW_CURRENT_TIME;
 ELSIF RISING_EDGE(CLK) THEN
     C_T:= I_CURRENT_TIME;
     IF C_T(0)< 9 THEN             
      C_T(0):=C_T(0)+1;
     ELSE        
      C_T(0) := 0;
       IF C_T(1)< 5 THEN
          C_T(1):= C_T(1)+1;
       ELSE
          C_T(1):= 0;
          IF C_T(3) < 2 THEN
          IF C_T(2) < 9 THEN
          C_T(2):= C_T(2)+1;
        ELSE
          C_T(2):= 0;
          C_T(3):= C_T(3)+1;
       END IF;
        ELSE
          IF C_T(2)<3 THEN
             C_T(2):= C_T(2)+1;
          ELSE
             C_T(2):=0;
             C_T(3):=0;
            END IF;
          END IF;
        END IF;
      END IF;
      I_CURRENT_TIME<=C_T;
  END IF;
   END PROCESS;
   CURRENT_TIME<=I_CURRENT_TIME;
END ARCHITECTURE ART;