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Both the preset and reset signals are active low, controlling the output of the DFFE whenever either signal goes low.</P>For more information on using this example in your project, go to:<UL TYPE=DISC> <LI><A HREF="verilog.html#using">How to Use Verilog HDL Examples</A> <LI>MAX+PLUS II Help</UL></P><HR noshade><P><B><I>dffeveri.v</I></B></P><PRE>module dffeveri (q, d, clk, ena, rsn, prn);// port declarationinput d, clk, ena, rsn, prn;output q;reg q;always @ (posedge clk or negedge rsn or negedge prn) begin//asynchronous active-low preset if (~prn) begin if (rsn) q = 1'b1; else q = 1'bx; end//asynchronous active-low reset else if (~rsn) q = 1'b0;//enable else if (ena) q = d;endendmodule</PRE><HR noshade><h2>Feedback</h2><p>Did this information help you?</p><p>If no, please log onto <a href="https://mysupport.altera.com/eservice/">mySupport</a> to file a technical request or enhancement.</p><p><hr noshade></p><font size="-1">Altera does not warrant that this solution will work for the customer's intended purpose and disclaims all liability for use of or reliance on the solution.</font><!-- end content --><!--stopindex--> <p> </p> </td> <td rowspan="3" width="15"><img src="/common/template/spacer.gif" width="15" height="15" alt="" border="0"></td> </tr> <tr valign="top"> <td bgcolor="#e0e0e0" valign="top" width="161"> </td></tr><tr> <td bgcolor=#e0e0e0 valign="bottom" width="161" height="2"> <p class="footer"> <br> Contact Us<br> <a href="/corporate/contact/info/con-feedback_form.jsp">Please Give Us Feedback</a><br> <a href="/corporate/contact/signup/con-signup.jsp">Sign Up for E-mail Updates</a></p> </td></tr><!-- Footer Information --> <tr><td bgcolor="#0182C4" colspan="4" align="right"><img src="/common/template/footer_user.gif" width="761" height="18" usemap="#footer_user" border="0" alt="footer"><map name="footer_user"><area shape="rect" coords="521,3,578,16" href="/common/new_user.html" alt="New User to the Altera Web Site" title="New User to the Altera Web Site"><area shape="rect" coords="587,4,631,15" href="/common/sitemap.html" alt="Altera Site Map" title="Altera Site Map"><area shape="rect" coords="643,3,684,14" href="/common/privacy.html" alt="Altera Privacy Policy" title="Altera Privacy Policy"><area shape="rect" coords="690,3,757,14" href="/common/legal.html" alt="Altera Legal Notice" title="Altera Legal Notice"></map></td> </tr><tr> <td width="161"> </td> <td colspan="3" width="100%"class="footer"><br><!-- begin top level navigation (bottom) --><a href=/index.jsp>Home</a> | <a href=/products/prd-index.html>Products</a> | <a href=/support/spt-index.html>Support</a> | <a href=/solutions/sln-index.html>System Solutions</a> | <a href=/education/edu-index.html>Education & Events</a> | <a href=http://buy.altera.com/ecommerce/>Buy On-Line</a> | <a href=/corporate/crp-index.html>Corporate</a><br><!-- end top level navigation (bottom) --> <!-- begin second level navigation (bottom) --><a href=/mysupport >mySupport</a> | <a href=/support/kdb/spt-search_kdb.html>Knowledge Database</a> | <a href=/support/software/sof-index.html>Software</a> | <a href=/support/devices/dvs-index.html>Devices</a> | <a href=/support/examples/exm-index.html>Design Examples</a><br><!-- end second level navigation (bottom) --> <p class="footer">Copyright © 1995 - 2002 Altera Corporation, 101 Innovation Drive, San Jose, California 95134, USA.</p> </td> </tr> </table> </td></tr></table><!--startindex--></body></html>?? 快捷鍵說明
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