Issue link: https://resources.pcb.cadence.com/i/1180526
PSpice User Guide Digital device modeling October 2019 408 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. The PINDLY primitive also allows constraint checking of the model. It can verify the setup, hold times, pulse width, and frequency. It also has a general mechanism to allow for user-defined conditions to be reported. The constraint checking only reports timing violations; it does not affect the propagation delay or the logic state of the device. Since the timing parameters are generally specified at the pin level of the actual device, the checking is normally done at the interface pins of the subcircuit after the appropriate buffering has been done. BOOLEAN The keyword BOOLEAN begins the boolean assignments which define temporary variables that can be used later in the PINDLY primitive. The form is: boolean variable = {boolean expression} The curly braces are required. In the 74160 model, the boolean expressions are actually reference functions. There are three reference functions available: CHANGED, CHANGED_LH, and CHANGED_HL. The format is: function name (node, delta time) For our example, we define the variable CLOCK as a logical TRUE if there has been a LO-to-HI transition of the CLK signal at simulation time. We define CNTENT as TRUE if there has been any transition of the ENT signal at the simulation time. Boolean operators take the following boolean values as operands: ■ reference functions ■ transition functions ■ previously assigned boolean variables ■ boolean constants TRUE and FALSE Transition functions have the general form of: TRN_pn