Question

我试图用两个按钮递增和递减。算法顺利，但我有一点问题。据说我正在递增，当我尝试递减累加器时，它再次递增，并且只有在它开始之后递减如果我先尝试递减，也一样。如果有人帮助我，我将非常感激。

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
use IEEE.std_logic_unsigned.all;

entity my_offset_controller is
port(clk            : in std_logic;
     input          : in std_logic_vector(15 downto 0);  
     add_button     : in std_logic;  
     sub_button     : in std_logic; 
     output_res     : out std_logic_vector(15 downto 0)
  );  
end my_offset_controller;

architecture Behavioral of my_offset_controller is

signal buttonState_up        : std_logic:='0';
signal accumulator           : std_logic_vector(15 downto 0);
signal lastButtonState_up    : std_logic:='0';
signal buttonState_down      : std_logic:='0';
signal lastButtonState_down  : std_logic:='0';
signal buttonPushCounter     : integer range 0 to 512 :=0;
process(clk)
      begin
        if rising_edge(clk) then 
              buttonState_up   <= add_button;
              buttonState_down <= sub_button;
                   if (buttonState_up /= lastButtonState_up) then 
                              if (buttonState_up ='1')       then 
                                    buttonPushCounter  <=  buttonPushCounter + 1;
                                    accumulator        <=   std_logic_vector(to_unsigned(buttonPushCounter,accumulator'length)); 
                               end if;
                      lastButtonState_up <= buttonState_up;      
                    elsif (buttonState_down /= lastButtonState_down) then 
                              if (buttonState_down ='1')       then 
                                   buttonPushCounter   <=  buttonPushCounter - 1;
                                accumulator        <=  std_logic_vector(to_unsigned(buttonPushCounter,accumulator'length)); 

                               end if;
                     lastButtonState_down <= buttonState_down;
                            end if;
                     end if;
     end process; 

output_res<= accumulator + input ;

这个特别模块用于控制我在vga屏幕上绘制的信号的偏移量。

Answer 1

如果没有更多信息，很难帮助您。您应该提供一个带有计时码表的测试平台，以便更轻松。然而，通过查看您的过程，我会说问题来自以下几行：

buttonPushCounter  <=  buttonPushCounter + 1;
accumulator        <=  std_logic_vector(to_unsigned(buttonPushCounter,accumulator'length));

在您更新buttonPushCounter的同时，您所执行的操作会增加accumulator。这种方式buttonPushCounter总是会移动+1或-1，具体取决于最后一个事件。

我建议的是在每个时钟周期更新accumulator，而不是每次发生事件。例如：

 if rising_edge(clk) then 
    accumulator <= std_logic_vector(to_unsigned(buttonPushCounter,accumulator'length));
    ...

VHDL-递增和递减按钮

1 个答案: