NanDigits Design Automation

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3.3.  Insert Cells. 

• ECO cells can be added into connections between cells. For example the following n2996 net (in red means being selected) can be inserted several ECO cells. Select the connection by mouse-left-click on it. Press 'Insert cells into connections' button.

• Type in the cell number to be inserted.

• In ECO Cell select window, select INVX4

• Select complete Loop if more than 1 cells will be inserted.

• Two INVX4 are inserted as following.

• Adjust the cells positions as needed.

• Or you can add other type of cell which has more than one input. For example AND cell.

• In Connectivities selection window, Y and A are default set to 'Complete Loop', B's default is 'Undriven'. You can choose 'Driven by' option. And in the entry, type in the net name or use fast way, mouse-left-click in the entry to activate it, mouse-left-click the net that should drive B, n1067 in this case. 

• AND2X4 is inserted with the connections specified above.

• Double click ECO cell AND2X4 to edit the cell. Or mouse-right-click to popup menu and select 'Edit cell'. Change instance name and add some comments.

• Cell instance is changed and comments are added as the following figure shown.

• You can move the comment's position to make the Schematic clean and readable. Mouse-right-click to choose 'Move comment'.

• Then mouse-left-press on the comment, move and release.

• Save ECO. And check ECO. Tcl format is listed below.
• # ECO insert cells.
• current_design fogdeep
  disconnect_net [get_nets n2996] [get_pins U2605/B]
  create_cell eco012345_and_out tsmc90.synth/AND2X4
  create_net n2996_eco012345_2
  connect_net [get_nets n2996_eco012345_2] [get_pins U2605/B]
  connect_net [get_nets n2996] [get_pins eco012345_and_out/A]
  connect_net [get_nets n2996_eco012345_2] [get_pins eco012345_and_out/Y]
  connect_net [get_nets n1067] [get_pins eco012345_and_out/B]
  

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