[Innovus] How to relative place 2 standard cells abut?

Hi,
in Innovus the relative placement is called structured data path (SDP). You can define an SDP group for the two registers and the placer will make sure to place them next to each other.
The SDP constraints are applied prior to placing the design, using either TCL commands or an SDP file with a dedicated format.
If you leave the group floating, i.e. without defining an origin, then the placer will decide on itself where the optimal location for the group is.

More details about SDP can be found in the Innovus user guide here: Using Structured Data Paths

Please pay attention to the examples in the user guide, as you need to set some switches to make place_design honor the SDP groups.

Dimo

Hi Dimo, 

I tried SDP with 2 switch -place_global_sdp_place true and -place_global_sdp_alignment true at place_opt_design, but don't know why innovus create so many SDP groups that I do not define. Each innovus-inferred SDP group contains ~ 20 flops that cause many short violations. 

Please help to review if my settings are correct.

Many thanks,

The following two settings should be just enough to create a single SDP group with the two registers:
setPlaceMode -place_global_sdp_place true -place_global_sdp_alignment true
createSdpGroup -name topF -inst "FF1 FF2"  -type row
place_opt_design

The instance list for createSdpGroup supports the ’glob ’-style wildcards ’*’, representing one or more characters, and ’?’ representing exactly one character.
Did that maybe caused some more cells to be added to the group?

You can review your SDP groups prior to place_opt_design either in the GUI or by querying the database.

A visual representation of the content of the SDP groups in the design is available through the SDP browser.
To open the browser, open the menu ‘Floorplan’ -> Structured Data Path.
The browser window gives an overview of the existing SDP groups and its elements and offers a possibility to manipulate some of the SDP attributes.

The SDP groups that are not instantiated in another SDP group are called “top SDPs”. They are stored in the database as a list in the floorplan attribute .topSdps. Querying all SDP groups in the database can be done with:
innovus> dbGet top.fPlan.topSdps.??

Dimo

The following two settings should be just enough to create a single SDP group with the two registers:
setPlaceMode -place_global_sdp_place true -place_global_sdp_alignment true
createSdpGroup -name topF -inst "FF1 FF2"  -type row
place_opt_design

The instance list for createSdpGroup supports the ’glob ’-style wildcards ’*’, representing one or more characters, and ’?’ representing exactly one character.
Did that maybe caused some more cells to be added to the group?

You can review your SDP groups prior to place_opt_design either in the GUI or by querying the database.

A visual representation of the content of the SDP groups in the design is available through the SDP browser.
To open the browser, open the menu ‘Floorplan’ -> Structured Data Path.
The browser window gives an overview of the existing SDP groups and its elements and offers a possibility to manipulate some of the SDP attributes.

The SDP groups that are not instantiated in another SDP group are called “top SDPs”. They are stored in the database as a list in the floorplan attribute .topSdps. Querying all SDP groups in the database can be done with:
innovus> dbGet top.fPlan.topSdps.??

Dimo