# Ece 211 Lab Essay

Submitted By John123Doe
Words: 978
Pages: 4

Procedure
At first, we need to build a pre-fabricated 7 - Segment LED Display circuit. and then, write a software to display a number. To implement this we will use a seven- segment LED display chip and a PAL chip 74LS47 TTL (that uses the binary data to light the correct LED's in the 7-segment display). Now, both the 7-Segment LED Display and the PAL chip are connected to one another with an input voltage of 5 V. In our experiment, we would be using pin 16 of the PAL Chip as Vcc, pin 8 will be connected to the Ground, pins 1,2,6,and 7 will be connected as data lines to specify (in binary) the number that the selected display should use, and pins 9-15 will be connected to the 7-segment display as it's input, that is, the previous four-bit signal has now been decoded into a seven-bit signal using logic circuits inside the chip. For example, 0101 (a four bit signal) is the binary equivalent of the decimal value 5 (i.e. 0*8 + 1*4 + 0*2 + 1*1). Hence, we would like to light the segments a,f,g,c and d on the seven segment display. A table has been mentioned below under the Questions Section to demonstrate how that logic works.

After the hardware is constructed, the software needs to be written to control these displays. In order to do this we must first make a program using ABEL software which program the chip to function to our liking. To build this program, we must first figure out the logic that we want to implement and compare it to the logic generated by the computer. If both of these match, we will be able to run the chip on our breadboards.

Questions

1. R=VrImax

1000=5-1.6-.05Imax

Imax=2.9mA

2. and 3.

| Input | Output | Deci | I1 | I2 | I4 | I8 | | a | b | c | D | e | f | g | 0 | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 2 | 0 | 0 | 1 | 0 | | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 3 | 0 | 0 | 1 | 1 | | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 4 | 0 | 1 | 0 | 0 | | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 5 | 0 | 1 | 0 | 1 | | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 6 | 0 | 1 | 1 | 0 | | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 7 | 0 | 1 | 1 | 1 | | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 8 | 1 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 9 | 1 | 0 | 0 | 1 | | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 10 | 1 | 0 | 1 | 0 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 11 | 1 | 0 | 1 | 1 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 12 | 1 | 1 | 0 | 0 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 13 | 1 | 1 | 0 | 1 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 14 | 1 | 1 | 1 | 0 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 15 | 1 | 1 | 1 | 1 | | 0 | 1 | 1 | 0 | 0 | 0 | 0 |

a=A'*B*C'*D' + A'*B'*C'*D b=A*C + A*B + B*C*D' + B*C'*D c=A*C + A*B + B'*C*D' d=A*B*C'*D' + A'*B'*C'*D + A'*B*C*D e=A'*D + B'*C'*D + A'*B*C' f=A'*C*D +A'*B'*C + A'*B'*D g=A'*B'*C' +…