用FPGA驱动AD7714程序编译出错，谁帮帮忙指点一下

只看该作者 · 2010-11-16 09:20

LIBRARY IEEE;
USE IEEE.std_logic_1164.all;
ENTITY AD7714xiaosong IS
   PORT(
      AD7714sclk:OUT std_logic;
      AD7714pol:OUT std_logic;
      AD7714sync:OUT std_logic;
      AD7714reset:OUT std_logic;
      AD7714standby:OUT std_logic;
      AD7714din:OUT std_logic;
      AD7714cs:OUT std_logic;
      AD7714drdy:IN std_logic;
      AD7714dout:IN std_logic;
      AD7714buffer:OUT std_logic;
      clk:IN std_logic
      );
END AD7714xiaosong;
ARCHITECTURE AD7714DATA OF AD7714xiaosong IS
   SIGNAL Read_AD7714DATA:std_logic_vector(23 downto 0);
   SIGNAL AD7714in_DATA:std_logic_vector(7 downto 0);
   BEGIN
   PROCESS(clk)
      VARIABLE i:INTEGER RANGE 0 TO 6;
      VARIABLE m:INTEGER RANGE 0 TO 23;
      VARIABLE n:INTEGER RANGE 0 TO 6;                                              --读数据
   BEGIN
      AD7714pol<='1';                            --初始化
      AD7714sync<='1';
      AD7714standby<='1';
      AD7714buffer<='1';
      AD7714cs<='0';
      AD7714reset<='1';
      IF(clk'EVENT and clk='1')THEN
            IF n<8 THEN
               CASE n IS
               WHEN 0 => AD7714in_DATA<="00100000";
               WHEN 1 => AD7714in_DATA<="00010001";
               WHEN 2 => AD7714in_DATA<="00110000";
               WHEN 3 => AD7714in_DATA<="00000000";
               WHEN 4 => AD7714in_DATA<="00010000";
               WHEN 5 => AD7714in_DATA<="00100000";
               WHEN 6 => AD7714in_DATA<="00011000";  --选择数据寄存器
               WHEN OTHERS => AD7714in_DATA<="00011000";
               END CASE;
            END IF;
               IF i< 8 THEN
               AD7714sclk<='0';
               AD7714din<=AD7714in_DATA(i);    --把数据写入AD7714
               i:=i+1;
               AD7714sclk<='1';
               ELSIF n=6 THEN
                           IF AD7714drdy='0' THEN          --如果AD有新数据产生，就读AD输出数据
                                       IF m<24 THEN
                                          AD7714sclk<='0';
                                          Read_AD7714DATA(m)<=AD7714dout;
                                          i:=0;
                                          AD7714sclk<='1';
                                       END IF;
                           END IF;
                        ELSE i:=0;
                        n:=n+1;
            END IF;

   END IF;

   END PROCESS;
END AD7714DATA;