connections to abstract not verified by Assura LVS - what's wrong?

Hi Trevor

Thank you for the detail info. Here is what I think:

a. Blackbox cell cannot be found by Assura
- Try using blackbox("cellName viewName libName")

b. erc file does not contain ip cell name
- This definitely means that the blackbox pins have not been extracted correctly
- Check if you have enabled cmds such as ?textPriOnly=t or ?textLevel=0:0
- Pin must be extracted for the blackbox in order for it to be properly compared
- Since your extract rule file only contains pinLayer and textToPin cmds, you should ensure that the text origin overlaps the dfII pin shapes. Otherwise the shapes will be extracted without pin names. This is usually not necessary if pinText cmds are present. pinText reads the names of the dfII pins
- If your current ip block only contains dfII pins and not text, please place the appropriate text over the pins using the pin layer and its corresponding metal purpose

>>>running LVS at a lower level of the chip, in which the IP block exists as a top level cell.
I think perhaps what you meant is "running LVS at a lower level of the chip in which the IP block exists as a cell in the top level". This is ok. Blackboxes will work as long as they exist as cells and not as the top level cell being compared.

The blackbox cell should appear in both schematic and layout netlists. For your case, it should be similar to the following in the layout vnl netlist:

c "myIPblock layout myLib" BlackBox  VDD P      GND G      IN NONE    avC4 N(f)
 ;;
* 4 pins
* 4 nets
* 0 instances

In case you are checking the schematic and layout netlists using vldbToCdl cmd in a terminal window, please note that this cmd does not dump out the blackbox cells. Please use vldbToVnl instead:
unix>vldbToVnl design.ldb > design.ldb.ascii
unix>vldbToVnl design.sdb > design.sdb.ascii

For your information, if the contents of the ip block is not important and need not be extracted by lvs, you can also use ?blackBoxCell cmd in avParameters. The difference is that blackBox cmd allows shapes to be extracted normally during lvs and hence even though the ip cell will not be compared, parasitics can subsequently still be extracted from it. ?blackBoxCell only allows pins and some blackbox shapes to be extracted and so the final result is a true blackbox, not only for lvs comparison but also for parasitic extraction.


Best regards
Quek

Hi Trevor

Thank you for the detail info. Here is what I think:

a. Blackbox cell cannot be found by Assura
- Try using blackbox("cellName viewName libName")

b. erc file does not contain ip cell name
- This definitely means that the blackbox pins have not been extracted correctly
- Check if you have enabled cmds such as ?textPriOnly=t or ?textLevel=0:0
- Pin must be extracted for the blackbox in order for it to be properly compared
- Since your extract rule file only contains pinLayer and textToPin cmds, you should ensure that the text origin overlaps the dfII pin shapes. Otherwise the shapes will be extracted without pin names. This is usually not necessary if pinText cmds are present. pinText reads the names of the dfII pins
- If your current ip block only contains dfII pins and not text, please place the appropriate text over the pins using the pin layer and its corresponding metal purpose

>>>running LVS at a lower level of the chip, in which the IP block exists as a top level cell.
I think perhaps what you meant is "running LVS at a lower level of the chip in which the IP block exists as a cell in the top level". This is ok. Blackboxes will work as long as they exist as cells and not as the top level cell being compared.

The blackbox cell should appear in both schematic and layout netlists. For your case, it should be similar to the following in the layout vnl netlist:

c "myIPblock layout myLib" BlackBox  VDD P      GND G      IN NONE    avC4 N(f)
 ;;
* 4 pins
* 4 nets
* 0 instances

In case you are checking the schematic and layout netlists using vldbToCdl cmd in a terminal window, please note that this cmd does not dump out the blackbox cells. Please use vldbToVnl instead:
unix>vldbToVnl design.ldb > design.ldb.ascii
unix>vldbToVnl design.sdb > design.sdb.ascii

For your information, if the contents of the ip block is not important and need not be extracted by lvs, you can also use ?blackBoxCell cmd in avParameters. The difference is that blackBox cmd allows shapes to be extracted normally during lvs and hence even though the ip cell will not be compared, parasitics can subsequently still be extracted from it. ?blackBoxCell only allows pins and some blackbox shapes to be extracted and so the final result is a true blackbox, not only for lvs comparison but also for parasitic extraction.


Best regards
Quek