3.1 PRS Supply Override

To override the supplies use to drive production rules (pull-up and pull-down) and pass-gates, we can write:

     prs <myVdd> {
     ... // These rules use myVdd to pull-up, and !GND for pull-down
     }
     prs <myVdd, myGND> {
     ... // Use myVdd to pull-up, myGND to pull-down
     }
     prs < , myGND> {
     ... // Use !Vdd to pull-up, myGND to pull-down
     }

Rules that balong to a supply domain will use the specified supply node for the drain of the foot transistor(s), and for the substrate (body) terminal.

     prs <myVdd,myGND> {
       x & y -> z-
     }
     // begets:
     M0 myGND x #0 myGND nch W=5u L=2u
     M1 #0 y z myGND nch W=5u L=2u

Normally, single-supply domain circuits need not be written with explicit production rule supply overrides. Instead, they can be connected externally to different supplies when instantiated, which is described in the next section.