This program was developed in several days to meet the following problem specification:
Develop a boolean logic simulator that will take two input files and create wire traces of the input and output wires (as specified in the files). Specifically, one file will detail the circuit (called the “circuit file”), while one will detail how each input wire changes as time goes by (called the “vector file”).
When run, the program will ask for a circuit name. This will be used to open two files (.txt and _v.txt). The first is the Circuit file and the second is the Vector file. These files will be detailed later. It will also ask for a time to simulate the circuit to. This time is used in the case of oscillating (i.e. unstable) wires.
There are several caveats to this project: there is no error handling for badly written Circuit/Vector files, and there are only seven gates to choose from (NOT, OR, AND, NOR, NAND, XOR, XNOR).
The file structure is detailed below.
The circuit file will follow the format below:
CIRCUIT HEADER
INPUT PAD DEFINITIONS
OUTPUT PAD DEFINITIONS
GATE DEFINITIONS
The CIRCUIT HEADER simply contains the keyword "CIRCUIT" followed by a circuit name. This name is simply for user reference, as the program discards this line.
The INPUT PAD DEFINITIONS consist of the keyword "INPUT" followed by a name for the input and a wire number to associate this input with.
The OUTPUT PAD DEFINITIONS are identical to INPUT PAD DEFINITIONS, except "INPUT" is replaced with "OUTPUT."
The GATE DEFINITIONS begins with the gate type (using keyword "NOT," "AND," "OR," "XOR," "NAND," "NOR," or "XNOR"), followed by a delay, followed by the inputs and outputs to the gate. It should be noted that each gate only accepts two inputs, with the exception of NOT, which only accepts one.
An example circuit file is shown below:
CIRCUIT ExampleCircuit
INPUT A 1
INPUT B 2
OUTPUT C 3
AND 2ns 1 2 3
The vector file will follow the format below:
VECTOR HEADER
INPUT PAD VALUE DEFINITIONS
The VECTOR HEADER simply contains the keyword "VECTOR" and a name for the vector. Similar to the circuit header, this line is purely for user reference. The program does not use it.
The INPUT PAD VALUE DEFINITIONS consist of the keyword "INPUT" followed by the name of an existing input, a time at which the specified input's value will change, and the value that the input will change to.
An example vector file is shown below:
VECTOR SimpleCircuit
INPUT A 0 0
INPUT B 0 0
INPUT A 4 1
INPUT B 5 1
Please enter filename: circuit2
What time do you want to simulate to (default 60ns)?
Wire Traces:
A: ______-----------------
B: ---------______________
C: ____-------------------
D: ------------xxxxxxxxxxx
E: xxxxxxxxxxxxxxxx______x
TIME: 0....5....10...15...20...25
Please enter filename: circuit4
What time do you want to simulate to (default 60ns)?
Wire Traces:
A: _------------------------------------------------------------
C: xx-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_x-x_
TIME: 0....5....10...15...20...25...30...35...40...45...50...55...60