Purpose of the Experiment
    The purpose of this experiment is to fix the nonsensical display chracters from a hex keyboard that are between the values of A and F. And reimpliment the value of the number six to read differently so as not to get it confused with a hex display character of B.

Theory
    The theory behind changing the characters is to change the value's corresponding display bits in each of the functions. Each function stands for one segment of the LED display module in an eight segment display module. The 'dot' segment will not be used in this experiment at all. Hence, there are only a total of seven functions for each of their corresponding display segments.
    Each of the functions, once a truth table is drawn up for them, will be Kmapped. An algebraic function will be derived from the Kmap. Once simpilfied, this algebraic function will be implimented into a circuit. Each function will be a subcircuit that will each segment of the display module.

Data

 
KMAP of f(a)
AB\CD
00
01
11
10
00
0
1
1
0
01
1
1
1
1
11
1
0
1
1
10
0
1
0
1
 
KMAP of f(b)
AB\CD
00
01
11
10
00
0
1
0
1
01
1
1
0
0
11
1
0
0
1
10
1
1
1
0
 
KMAP of f(c)
AB\CD
00
01
11
10
00
0
1
0
1
01
0
1
0
1
11
1
1
0
1
10
1
1
1
1
 
KMAP of f(d)
AB\CD
00
01
11
10
00
0
1
1
0
01
1
1
1
1
11
1
1
0
0
10
0
0
1
1
 
 
KMAP of f(e)
AB\CD
00
01
11
10
00
0
1
1
0
01
1
1
1
1
11
0
1
1
0
10
0
0
1
0
 
 
KMAP of f(f)
AB\CD
00
01
11
10
00
0
1
1
1
01
0
0
1
1
11
0
1
1
0
10
0
1
0
1
 
 
KMAP of f(g)
AB\CD
00
01
11
10
00
0
1
0
1
01
1
1
1
1
11
1
1
1
0
10
0
1
1
1

Circuit Diagram

Results
    The circuit above was designed to implement the functions that were derived from the KMAP for each segment. Each KMAP corresponds to the individual sections of the LED display. Each of the subciruits receives four inputs and has one output. The four inputs correspond to the HEX's board layout of the outputs letters A, B, C, and D. Each subciruit parses the output from the hex keyboard and outputs a logical one or zero directly to the display. Each subcircuit handles exactly one of the inputs of the LED display screen.
    Hence, when as user enters 'A' into the hex keyboard, the signal 0101 sent out from the keyboard. Each of the 7 subcircuits receive this signal and parse it according to their own truth tables. When the parsing is done, the output is sent directly to the corresponding input of the LED display screen. Therefore, when 0101 gets sent out, subcircuit A receives this and sends out an '0' to the LED display screen. The second circuit layout demonstrates this modified circuit. Further results would be demonstrated upon demand.

Conclusions
    This simulation was quite a thought provoking one. The biggest problem was the use of the LogicWorks program to create custom chips and custom subcircuits. The implimentation was the actual circuit layout encapsulated and organised around the center of the layout. Also, to change any function, first one must be able to see the truth table for the entire function (and other reliant functions, as in the first table above). Then by changing the relevant bits, re-deriving the kmaps and reimplimenting the functions one can impliment the modification! Also some reverse engineering was needed in this case. The chip itself was reimplimented and modifications added to the chip.
    Along these lines, there were several ways that this could have been accomplished. It was decided to accomplish the goal of fixing the characters by implimenting a concise approach. This concise approach was to be able to "see" into each of the subcircuits. Although the major drawback for this method was that too much space was taken up by the components. Just compare the first diagram and second diagram.