Question

In Figure 1 a conceptual diagram of a seven-segment screen is presented, called a, b, c, d, e, f and g, as well as a decimal point dp. In this work, it is not considered the decimal point.

Figure 1: Seven-Segment Screen

Each of the segments is a light-emitting diode (LED). The screen is used for representing numbers or other symbols. If the screen is a common cathode, then when a high voltage appears (logical value 1) the respective LED lights up. In Figure 2, the numerals 0 to F of the hexadecimal system are represented. Note that for the c, d and b we used lowercase letters to avoid interpretation issues. In this picture it has been assumed that a “1” is needed to turn on the LED (in black), that is, a screen has been assumed as a common cathode screen. For figures 0 and 1, it has been indicated in the respective terminals where to place 1 and where the place 0.

Figure 2: Hexadecimal Figures

In the common anode screen, the LED lights up with a logical 0, and turns off with a logical 1. In the common cathode screen, the LED lights up with a logical 1, and turns off with a logical 0. Seven-segment displays can be managed with appropriate subsystems. One of them is the codifier BCD-to-Seven-Segment, which has four entries representing a binary digit, and seven outputs to connect to the screen, so that the screen turns on the LEDs corresponding to the decimal digit corresponding to the binary of the input.

The objective of this practice is to present a design for a Gray-to-Seven- Segment as illustrated in Figure 3 according to the specifications indicated below. The Gray code is a code for numbers. In the work to be done, the A3 A2 A1 A0 entries are read as if they correspond to a number between 0 and 15 in Gray code. The screen should show the hexadecimal number placed in the entrance.

Figure 3: Encoder to Design

Question 3: If we assume a common cathode screen, place at each entry the values ​​1 or 0 required for the representation of each hexadecimal digit.

OD OD OD LJ АЗ Hex A2 Gray A17 Seg to dp

Answer 1

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