//-------???????????????----- task shift8in;   begin     casex(sh8in_state)       sh8in_begin:          sh8in_state<=sh8in_bit7;       sh8in_bit7: if(SCL)                      begin                        data_from_rm[7]<=SDA;                        sh8in_state<=sh8in_bit6;                      end                    else                      sh8in_state<=sh8in_bit7;        sh8in_bit6: if(SCL)                      begin                          data_from_rm[6]<=SDA;                          sh8in_state<=sh8in_bit5;                      end                     else                       sh8in_state<=sh8in_bit6;        sh8in_bit5: if(SCL)                      begin                          data_from_rm[5]<=SDA;                          sh8in_state<=sh8in_bit4;                      end                    else                      sh8in_state<=sh8in_bit5;        sh8in_bit4:  if(SCL)                       begin                           data_from_rm[4]<=SDA;                           sh8in_state<=sh8in_bit3;                       end                      else                        sh8in_state<=sh8in_bit4;        sh8in_bit3:if(SCL)                       begin                          data_from_rm[3]<=SDA;                          sh8in_state<=sh8in_bit2;                       end                    else                       sh8in_state<=sh8in_bit3;        sh8in_bit2:  if(SCL)                         begin                          data_from_rm[2]<=SDA;                          sh8in_state<=sh8in_bit1;                        end                     else                       sh8in_state<=sh8in_bit2;        sh8in_bit1: if(SCL)                       begin                         data_from_rm[1]<=SDA;                         sh8in_state<=sh8in_bit0;                       end                    else                      sh8in_state<=sh8in_bit1;        sh8in_bit0: if(SCL)                       begin                          data_from_rm[0]<=SDA;                          sh8in_state<=sh8in_end;                       end                    else                      sh8in_state<=sh8in_bit0;        sh8in_end:  if(SCL)                        begin                            link_read<=YES;                            FF<=1;                            sh8in_state<=sh8in_bit7;                        end                    else                      sh8in_state<=sh8in_end;        default: begin                   link_read<=NO;                   sh8in_state<=sh8in_bit7;                end    endcase  endendtask                        //-------?????????????--------  task shift8_out;    begin      casex(sh8out_state)         sh8out_bit7:                                 if(!SCL)                 begin                    link_sda<=YES;                    link_write<=YES;                    sh8out_state<=sh8out_bit6;                 end              else                sh8out_state<=sh8out_bit7;         sh8out_bit6:                if(!SCL)                  begin                     link_sda<=YES;                     link_write<=YES;                     sh8out_state<=sh8out_bit5;                     sh8out_buf<=sh8out_buf<<1;                               end                else                  sh8out_state<=sh8out_bit6;        sh8out_bit5:                if(!SCL)                    begin                        sh8out_state<=sh8out_bit4;                        sh8out_buf<=sh8out_buf<<1;                    end                else                  sh8out_state<=sh8out_bit5;        sh8out_bit4:                if(!SCL)                  begin                      sh8out_state<=sh8out_bit3;                      sh8out_buf<=sh8out_buf<<1;                  end                else                  sh8out_state<=sh8out_bit4;        sh8out_bit3:              if(!SCL)                 begin                     sh8out_state<=sh8out_bit2;                     sh8out_buf<=sh8out_buf<<1;                 end              else                sh8out_state<=sh8out_bit3;        sh8out_bit2:              if(!SCL)                  begin                      sh8out_state<=sh8out_bit1;                      sh8out_buf<=sh8out_buf<<1;                  end              else                sh8out_state<=sh8out_bit2;        sh8out_bit1:              if(!SCL)                 begin                    sh8out_state<=sh8out_bit0;                    sh8out_buf<=sh8out_buf<<1;                end              else                sh8out_state<=sh8out_bit1;        sh8out_bit0:              if(!SCL)                  begin                      sh8out_state<=sh8out_end;                      sh8out_buf<=sh8out_buf<<1;                                        end              else                sh8out_state<=sh8out_bit0;        sh8out_end:              if(!SCL)                  begin                      link_sda<=NO;                      link_write<=NO;                      FF<=1;                  end              else                sh8out_state<=sh8out_end;          endcase    endendtask                       //-----????????------ task shift_head;    // weile keyi shengcheng  xian 1---0   begin      casex(head_state)          head_begin:              if(!SCL)                 begin                     link_write<=NO;                     link_sda<=YES;                     link_head<=YES;                     head_state<=head_bit;                 end              else                 head_state<=head_begin;          head_bit:               if(SCL)                 begin                     FF<=1;                     head_buf<=head_buf<<1;//weile keyi shengcheng  xian 1---0                     head_state<=head_end;                 end                else                  head_state<=head_bit;          head_end:               if(!SCL)                 begin                     link_head<=NO;                     link_write<=YES;                 end                else                  head_state<=head_end;          endcase      end  endtask                               //--------????????----task shift_stop;    begin        casex(stop_state)            stop_begin: if(!SCL)                            begin                                link_sda<=YES;                                link_write<=NO;                                link_stop<=YES;                                stop_state<=stop_bit;                            end                        else                          stop_state<=stop_begin;            stop_bit:  if(SCL)                           begin                              stop_buf<=stop_buf<<1;                              stop_state<=stop_end;                          end                        else                          stop_state<=stop_bit;            stop_end: if(!SCL)    // fuzhi hou yao jinxing fuwei ,suoyi jiu zia bu tongde dianping lai jinxing                         begin                            link_head<=NO;                            link_stop<=NO;                            link_sda<=NO;                            FF<=1;                        end                      else                        stop_state<=stop_end;                endcase            end    endtaskendmodule