VHDL设计的串口通信程序

文章摘要： ELSE clkbaud_tras <= ’0’; END IF; END PROCESS; PROCESS(clkbaud8x,rst) BEGIN IF (NOT rst = ’1’) THEN txd_reg <= ’1’; trasstart <= ’0’; txd_buf <= "00000000"; state_tras <= "0000";

VHDL设计的串口通信程序,标签：eda技术,eda技术实用教程,http://www.88dzw.com
      ELSE
         clkbaud_tras <= ’0’;   
      END IF;
   END PROCESS;

   PROCESS(clkbaud8x,rst)
   BEGIN
      IF (NOT rst = ’1’) THEN
         txd_reg <= ’1’;   
         trasstart <= ’0’;   
         txd_buf <= "00000000";   
         state_tras <= "0000";   
         send_state <= "000";   
         key_entry2 <= ’0’;   
      ELSE IF(clkbaud8x’EVENT AND clkbaud8x = ’1’) THEN
         IF (NOT key_entry2 = ’1’) THEN
            IF (key_entry1 = ’1’) THEN
               key_entry2 <= ’1’;   
               txd_buf <= "01110111";   "w"
            END IF;
         ELSE
            CASE state_tras IS
               WHEN "0000" =>  发送起始位
                        IF ((NOT trasstart=’1’) AND (send_state < "111") ) THEN
                           trasstart <= ’1’;   
ELSE
                           IF (send_state < "111") THEN
                              IF (clkbaud_tras = ’1’) THEN
                                 txd_reg <= ’0’;   
                                 state_tras <= state_tras + "0001";   
                              END IF;
                           ELSE

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