src_en/api.change_gate.txt

<h3 id='___change_gate'>change_gate</h3>
<pre>ECO command. Modify an instance in ECO
Two types of usages
<b>Usage1:</b> change_gate($instance, $new_reference, $pin_mapping);
$instance: The instance under ECO. Support hierarchical name, "u_abc/U123"
$new_reference: The new reference name which the instance changes to, E.G. 'AND3X1'. 
                If no reference is present, the ECO operation is assumed to 
                  change the instance's pin connections.
$pin_mapping: Input pins mapping, ".new(old)", E.G. ".A1(A),.B1(B)"
              if two references have same input pins. The option can be empty
<b>Usage2:</b> change_gate($instance, $pin_connections);
$pin_connections: New pin connections, ".A(n242)".
                  The unspecified pins keeps the original connection.
                  E.G. pin 'B' connection is unchanged.

<b>Examples:</b>  

#1. U123 has reference OR3X1 with input pins, A,B,C originally
# change U123 to AND3X1, all input pins are the same.
change_gate('U123', 'AND3X1', ""); 

#2. A and B keep the connections, discard C
change_gate('U123', 'AND2X1', "");

#3. A keeps the connections, B connects to what the old C connects. And discard old B
change_gate('U123', 'AND2X1', ".B(C)"); 

#4. A,B,C keep the same, and new D pin connects to net n123
change_gate('U123', 'AND4X1', ".D(n123)"); 

#5. AO21X1 has input pins, A0, A1 and B0 
change_gate('U123', 'AO21X1', ".A0(A),.A1(B),.B0(C)");

#6. change U123 A to n123, B to n124, keep C connection. 
change_gate("U123", ".A(n123),.B(n124)"); 

#7. Rotating A/B/C connections.
change_gate("U123", ".A(B),.B(C),.C(A)"); 
</pre>