Gate Delay Specifications Keywords

The Gate Delay are used to specify the Propogation delay of each and every Gate element in the circuit under simulation. It can be called in the program after initailizing the circuit by using the keyword 

DELAY

By default the value of this propogation delay is 10 nanoseconds. The Propogation delay has to be specified in multiples of 1 nanosecond.

Therefore, AND 1.5n is not usable.

Correct usage would be
'AND 1n' or 'AND 2n' Either of them can be used.

Some usage examples are shown below!

DELAY
AND 2n           # ([Gate_type_name] in general)

The [Gate_type_name] (AND in this case) is to access all the AND Gates present in the Circuit and initialize with 2 nanoseconds of propogation Delay.

AND A B C
# Rest of the code..
DELAY
C 2n             # ([Ouput_Port] in general)

The [Output_Port] (or the AND gate with the output port named 'C' in this case) sets only the provided gate's propogation delay which is specified by its Output Port. Here the And Gate whose output port is C is accessed and assigned with a Propogation Delay of 2 nanoseconds. 

AND A B C        # 2 input AND gate
AND C B E F      # 3 input AND gate
# Rest of the code..
DELAY
AND 2 2n
AND 3 4n

Here the AND 2 implies the two input AND gates are intialized with the specified propogation delay. Similarly the AND 3 implies the AND gates with 3 inputs are initialized with the specified propogation delay.

Precedence of input DELAY specifications:

[Gate_Output] > AND n > AND


Here [Gate_Output] is the output port name of the Gate. AND n means the AND Gate with 'n' number of inputs. AND is the generic one used to mention all AND Gates.