I'm trying to connect a purely analog macro to the...
# caravel
e
I'm trying to connect a purely analog macro to the PDN. I have drawn two vertical bars of Metal 4 and labeled them as
vssd1
and
vccd1
(yellow text). On the GUI it looks like they both intersect with the corresponding horizontal blue Metal 5 bars of Caravel's PDN - is this right? Will they connect and be powered? Or do I have to extend the M4 horizontally instead, so they intersect with Caravels vertical M4 power strips? Thank you
m
@Ellen Wood just to clarify the problem. 1. You created an analog macro in magic or klayout. 2. You created the LEF representation of the macro. 3. You created a verilog rtl stub that contains all the pins. 4. (added) You added these LEF and verilog files to config.json 5. You added the
FP_PDN_MACRO_HOOK
variable to the config.json file and set the value to
inst vssd1 vccd1 vssd1 vccd1
6. You run openlane and the macro is not being connected?
e
Hi @Mitch Bailey, Steps 1-5 yes exactly. It was drawn in magic. Honestly I am not sure whether the macro is being connected to the power or not, because the run is failing due to a 'Metal 2 Short' design violation in Step 14. So no GDS is generated which I can inspect to see if my macro is connecting to the PDN. (unless there is a way to tell in the GUI?) In order to try and solve the short, I was going to re-draw the main power lines in my macro and include 2 more power connections. However, before I did this, I wanted to make sure the orientation of those bars is correct (ie, vertical and not horizontal)!
n
Hi, sorry for meddling, we had a similar issue last year. Take a look at the log in
logs/floorplan/6-pdn.log
. If is not connected, it will say
[WARNING PDN-0189] Supply pin [pin] of instance [instance] is not connected to any net.
We went with horizontal stripes, but mainly because we were trying to mimic what Harald Pretl did, so he and Mitch probably can give you a more informed answer.
m
@Ellen Wood There are several
QUIT_ON_
variables available. You could try setting those to zero to produce a gds file with errors. I image there’s a way to view the intermediate results with the openroad gui, but I can not give any advice on that.
e
Thank you both 🙂
👍 2
h
If the power straps are connected, you will see the corresponding via there. If no via (looks like it), then no connection. You can also read the layout into magic, and select a track (
s
-
s
-
s
) to highlight everything that is connected.