解析错误：意外的 WHEN，期望分号

Question

我正在尝试在 VHDL 中实现此 when else 语句，但由于某种原因，我收到此错误：

Line 48. parse error, unexpected WHEN, expecting SEMICOLON

第 48 行是这个：LED<= "1111001" when count_temp = "0001" else

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity SOURCE is
    Port (clk_in,RST : in  STD_LOGIC;
          COUNT : inout  STD_LOGIC_VECTOR (3 downto 0);
             AN: out std_logic_vector(3 downto 0);
             LED: out std_logic_vector(6 downto 0));
end SOURCE;

architecture Behavioral of SOURCE is

signal count_temp: std_logic_vector(3 downto 0);
signal CLK: std_logic;

component clk_div is
port (clk_in: in std_logic;
        clk_out: out std_logic);
end component;


begin
CL: clk_div port map (clk_in, CLK);

counter: process (CLK,RST,count_temp) 

begin
if (RST = '1')then
count_temp <= "0000";
elsif(rising_edge(CLK))then

    if (count_temp <= "1111") then
    count_temp <= count_temp +1;
    else count_temp <= "0000";
    end if;
end if;
end process;

COUNT <= count_temp;
AN <= "1110";

process(count_temp)

begin

LED<= "1111001" when count_temp = "0001" else
        "0100100" when count_temp = "0010" else
        "1111001" when count_temp = "0011" else
        "0100100" when count_temp = "0100" else
        "1111001" when count_temp = "0101" else
        "0100100" when count_temp = "0110" else
        "0100100" when count_temp = "0111" else
        "1111001" when count_temp = "1000" else
        "0100100" when count_temp = "1001" else
        "1111001" when count_temp = "1010" else
        "0100100" when count_temp = "1011" else
        "1111001" when count_temp = "1100" else
        "0100100" when count_temp = "1101" else
        "1111001" when count_temp = "1110" else
        "0100100" when count_temp = "1111" else
        "0100111" when others;
    
end process;

Answer 1

看起来可能有两件事：

1. 不确定您是否可以在像您这样的进程中使用条件信号分配。尝试移动到进程之外？
   2）。根据此页面 https://www.ics.uci.edu/~jmoorkan /vhdlref/cond_s_a.html。您编写 else 部分的方式看起来像是一些语法错误？也许只需要 else "0100111" （其他时候不需要）