请教~~~~~~~~~~~~~~~~~~~VHDL同时读取时钟上升沿和下降沿出现的出错问题
--我想要实现的功能：rMCU下降沿时输出数据，然后拉低wMCU表示数据已经准备好。等待rMCU拉高，然后wMCU拉高准备下一次读写.rMCU: input读
wMCU: output写
datout:数据输出。
rMCU: ~~~\________/~~~~~~~~\________/~~~~~~~~\__
datout: ~~~\AAAAAAAAAAAAAAAAA\BBBBBBBBBBBBBBBBB\CCCC
wMCU: ~~~~~\_____/~~~~~~~~~~~\_____/~~~~~~~~~~~\_
--以下是我写的程序
library ieee;
use ieee.std_logic_1164.all;
entity MCUtest is
port(rMCU: in std_logic;
wMCU: out std_logic;
datout: inout std_logic_vector(7 downto 0));
end MCUtest;
architecture behav of MCUtest is
signal datnum: integer range 0 to 8;
signal datstart: std_logic_vector(7 downto 0);
signal datx1h,daty1h,datx2h,daty2h,datx1l,daty1l,datx2l,daty2l: std_logic_vector(7 downto 0);
begin
datstart <= "10101010";
process(rMCU)
begin
if(rMCU'event and rMCU = '0') then
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
when 5 => datout <= datx2h;
when 6 => datout <= datx2l;
when 7 => datout <= daty2h;
when 8 => datout <= daty2l;
end case;
wMCU <= '0';
if(datnum = 8) then
datnum <= 0;
else
datnum <= datnum + 1;
end if;
end if;
if(rMCU'event and rMCU = '1') then
wMCU <= '1';
end if;
end process;
end behav;
问题是最后
if(rMCU'event and rMCU = '1') then
wMCU <= '1';
end if;
end process;
编译时出错
Error (10819): Netlist error at MCUtest.vhd(40): can't infer register for wMCU because it changes value on both rising and falling edges of the clock
请问怎么解决？
或者有其他什么样的编程方法吗？ 一个进程只能有一个边沿检测
试试这个,我没在Q2上试,也许有错.
begin
--datstart <= "10101010";--
process
begin
if(rMCU = '0') then
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
when 5 => datout <= datx2h;
when 6 => datout <= datx2l;
when 7 => datout <= daty2h;
when 8 => datout <= daty2l;
end case;
wMCU <= '0';
if(datnum = 8) then
datnum <= 0;
else
datnum <= datnum + 1;
end if;
else
wMCU <= '1';
end if;
end if;
wait on rMCU;
end process;
end behav; mark 回复【1楼】40130064
一个进程只能有一个边沿检测
试试这个,我没在q2上试,也许有错.
begin
--datstart <= "10101010";--
process
begin
if(rmcu = '0') then
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
......
-----------------------------------------------------------------------
试过，用户else也不行。一样的错误。
还有我开了两个进程，
architecture behav of MCUtest is
signal datnum: integer range 0 to 8;
signal datstart: std_logic_vector(7 downto 0);
signal datx1h,daty1h,datx2h,daty2h,datx1l,daty1l,datx2l,daty2l: std_logic_vector(7 downto 0);
begin
datstart <= "10101010";
process(rMCU)
begin
if(rMCU'event and rMCU = '0') then
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
when 5 => datout <= datx2h;
when 6 => datout <= datx2l;
when 7 => datout <= daty2h;
when 8 => datout <= daty2l;
end case;
wMCU <= '0';
if(datnum = 8) then
datnum <= 0;
else
datnum <= datnum + 1;
end if;
end if;
end process;
process(rMCU)
begin
if(rMCU'event and rMCU = '1') then
wMCU <= '1';
end if;
end process;
end behav;
这样会出现另外一个问题。是不能在两个进程对同一个寄存器附值。
最后我只能把wMCU去掉。 如果我想实现这个时序。应该怎么样子写呢？
rMCU: input读
wMCU: output写
datout:数据输出。
rMCU: ~~~\________/~~~~~~~~\________/~~~~~~~~\__
datout: ~~~\AAAAAAAAAAAAAAAAA\BBBBBBBBBBBBBBBBB\CCCC
wMCU: ~~~~~\_____/~~~~~~~~~~~\_____/~~~~~~~~~~~\_ 你没试 我用的wait on rMCU;rMCU变化进程运行一次只一个敏感信号 不过好像多了个END IF
你要是用这个和MCU通信 方法都不对 begin
speaker <= '1';
--datstart <= "10101010";--
process
begin
if(rMCU = '0') then
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
when 5 => datout <= datx2h;
when 6 => datout <= datx2l;
when 7 => datout <= daty2h;
when 8 => datout <= daty2l;
end case;
wMCU <= '0';
if(datnum = 8) then
datnum <= 0;
else
datnum <= datnum + 1;
end if;
else
wMCU <= '1';
end if;
wait on rMCU;
end process;
end behav;
Error (10533): VHDL Wait Statement error at mouse.vhd(42): Wait Statement must contain condition clause with UNTIL keyword
楼上的大哥，不好意思。刚才看到你的else以为是我测试过的那个。你这个我也测试了。还是不对。你说的方法是哪种？我现在MCU就只有10个IO脚可以用。其他的都被占用了。 还有，你说的变化一次是只从1->0还是从0->1还是从1->0->1呢？ library ieee;
use ieee.std_logic_1164.all;
entity MCUtest is
port(rMCU: in std_logic;
wMCU: out std_logic;
datout: inout std_logic_vector(7 downto 0));
end MCUtest;
architecture behav of MCUtest is
signal flag: std_logic;
signal datnum: integer range 0 to 8;
signal datstart: std_logic_vector(7 downto 0);
begin
datstart <= "10101010";
process(rMCU)
begin
if(flag = '1') then
flag <= '0';
wMCU <= '1';
else
if(rMCU'event and rMCU = '0') then
flag <= '1';
case(datnum) is
when 0 => datout <= datstart;
when 1 => datout <= datx1h;
when 2 => datout <= datx1l;
when 3 => datout <= daty1h;
when 4 => datout <= daty1l;
when 5 => datout <= datx2h;
when 6 => datout <= datx2l;
when 7 => datout <= daty2h;
when 8 => datout <= daty2l;
end case;
wMCU <= '0';
if(datnum = 8) then
datnum <= 0;
else
datnum <= datnum + 1;
end if;
end if;
end if;
end process;
end behav;
楼上的大哥，我根据你那个1次进入一次进程写的。这样就能通过了。不过总觉得这样写好样有点。。。。 这里果然不支持TAB键的。。。
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