解决方法:使用“异或”(xor)逻辑。示例如下:
process (CLK)
begin
if rising_edge(CLK) then
SIG_RISE_OUT <= SIG_FALL_OUT xor D_IN0;
end if;
end process;
process (CLK)
begin
if falling_edge(CLK) then
SIG_FALL_OUT <= SIG_RISE_OUT xor D_IN1;
end if;
end process;
D_OUT <= SIG_RISE_OUT xor SIG_FALL_OUT;