我有一个与从 numeric_std 转换为 std_logic_vector 相关的问题。我正在使用我在网上看到的移动平均滤波器代码并过滤我的 ADC 值以稳定这些值。
过滤器包代码为:
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
package filterpack is
subtype number is unsigned(27 downto 0);
type numbers is array(natural range <>) of number;
function slv_to_num(signal slv: in std_logic_vector) return number;
procedure MAF_filter(
signal x: in number;
signal h: inout numbers;
signal y: out number
);
end filterpack;
package body filterpack is
function slv_to_num(signal slv: in std_logic_vector) return number is
variable x: number := (others => '0');
begin
for i in slv'range loop
if slv(i) = '1' then
x(i+4) := '1';
end if;
end loop;
return x;
end function slv_to_num;
procedure MAF_filter(
signal x: in number;
signal h: inout numbers;
signal y: out number
) is
begin
h(0) <= x + h(1); -- h[n] = x[n] + h[n-1]
y <= h(0) - h(h'high); -- y[n] = h[n] - h[n-M]
end MAF_filter;
end package body filterpack;
在我的顶级文件中,我调用了 MAF_filter 过程。
Asign_x: x <= slv_to_num(adc_dat);
Filter: MAF_filter(x,h,y);
adc_dat 定义为:
adc_dat : out std_logic_vector (23 downto 0);
我想将 MAF_Filter 的输出转换为 std_logic_vector (23 down to 0)。谁能告诉我如何将过滤器输出“y”转换为“std_logic_vector”?
非常感谢!