asyncmc.vhd

基于VHDL的串行异步通信电路的设计 包括串行发送器

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_SIGNED.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY ASYNCMC IS
PORT(
     DIN: IN STD_LOGIC_VECTOR(7 DOWNTO 0);
     DOUT:OUT STD_LOGIC_VECTOR(7 DOWNTO 0);
     CS,RD,WR,A0,TXC,RXC,RXD,RESET: IN STD_LOGIC;
     STS:OUT STD_LOGIC_VECTOR(7 DOWNTO 0);
     TIRQ,RIRQ,TXD,CLK: OUT STD_LOGIC);
END;

ARCHITECTURE MAIN OF ASYNCMC IS
SIGNAL REG_STATUS,INPUT,OUTPUT,DDDD: STD_LOGIC_VECTOR(7 DOWNTO 0);
SIGNAL TEMP,TXD_TEMP,TXD3,ETBE,ERBF,ERXE,TBE,FE,OE,PE,RBF,START:STD_LOGIC;
COMPONENT TxMITER
PORT(
     INPUT: IN STD_LOGIC_VECTOR(7 DOWNTO 0);
     RESET,TCLK,WR,ETBE,CS,A0: IN STD_LOGIC;
     OUTPUT,TBE: OUT STD_LOGIC;
     TIRQ,CLK,START: OUT STD_LOGIC);
END COMPONENT;

COMPONENT ASYNRCV
PORT(
     RESET,RXC,RXD,RE,ERBF,ERXE,CS,A0: IN STD_LOGIC;
     OUTPUT: OUT STD_LOGIC_VECTOR(7 DOWNTO 0);
     FE,OE,PE,RBF,RIRQ: OUT STD_LOGIC);
END COMPONENT;

BEGIN
U1: TxMITER PORT MAP (INPUT,RESET,TXC,WR,ETBE,CS,A0,TXD3,TBE,TIRQ,CLK,START);
U2: ASYNRCV PORT MAP (RESET,RXC,TXD_TEMP,RD,ERBF,ERXE,CS,A0,OUTPUT,FE,OE,PE,RBF,RIRQ);
PROCESS(RXC,CS,A0,RD,WR)
VARIABLE STAT:STD_LOGIC_VECTOR(3 DOWNTO 0);
VARIABLE REG_STATUS:STD_LOGIC_VECTOR(7 DOWNTO 0);
BEGIN
STAT:=CS&A0&RD≀
   IF RXC'EVENT AND RXC='1' THEN
    IF RESET='0' THEN
       TEMP<='0';REG_STATUS:="00000000";TXD_TEMP<='1';DDDD<="00000000";ETBE<='0';ERBF<='0';INPUT<="00000000";ERXE<='0';
    ELSE

     IF TEMP='0' THEN
         REG_STATUS:="00000010";
         TEMP<='1';TXD_TEMP<='1';
     ELSIF START='1' THEN TXD_TEMP<=TXD3;
     END IF;
            REG_STATUS:='0'&'0'&'0'&FE&OE&PE&TBE&RBF;

       CASE STAT IS
         WHEN "0001"=>DDDD<=OUTPUT;
         WHEN "0010"=>INPUT<=DIN;
         WHEN "0101"=>
            DDDD<=REG_STATUS;
         WHEN "0110"=>
            ETBE<=DIN(1);
            ERBF<=DIN(0);
            ERXE<=DIN(2);
         WHEN OTHERS=>DDDD<=DDDD;
    
       END CASE;


          
    END IF; 
  END IF;

END PROCESS;

STS<='0'&'0'&'0'&FE&OE&PE&TBE&RBF;
TXD<=TXD_TEMP;
DOUT<="ZZZZZZZZ" WHEN CS='1' ELSE DDDD;

END;