Clock & Timer Circuit DiagramsCounter Circuit DiagramsOscillators Circuit Diagrams

Digital Pattern Generator Schematic Circuit Diagram

Creating Defined Bit Patterns: Digital Pattern Generator

Digital pattern generator: In the realm of constructing and testing digital circuits, there is a frequent requirement for accurately defined bit patterns. The described generator employs an EPROM to store the bit information corresponding to the desired pattern. Upon pressing switch S1, a specific pattern is generated once, and up to seven distinct patterns can be simultaneously generated. The eighth data output of the EPROM is utilized to signify the end of a pattern.

Address Counter Reset and Clock Frequency Control

After the activation of S1, gate ICid orchestrates the reset of the address counter IC2. Gate 1C1c, linked to the address counter’s input, operates as a start-stop oscillator controlled by two NAND gates. These gates ensure the oscillator remains inactive until the switch is released, allowing pulses to be directed to the address counter. The clock’s frequency range can be adjusted to suit specific needs by modifying the value of C3. With the provided values, P1 can set the frequency between 15 Hz and 150 Hz.

Bit Pattern Generation and Circuit Characteristics

For a generated bit pattern, it is imperative for data line D7 to be logic high. At the pattern’s conclusion, this line transitions to low, halting the clock. In the demonstrated circuit, the maximum bit pattern length is 8191 clock pulses (8×1024-1 stop pulse). If link_JP1 is positioned at B, an external stop pulse can be applied. The circuit operates with a current draw of approximately 8 mA.

Digital pattern generator Schematic diagram

Preserving Data Beyond Power Cycles: Understanding EPROM

EPROM, an abbreviation for erasable programmable read-only memory (occasionally EROM), stands as a variety of programmable read-only memory (PROM) chip that retains its stored data even when its power supply is turned off. Memory capable of retrieving information after a power cycle is termed non-volatile. It comprises an array of floating-gate transistors, individually programmed by an electronic device using higher voltages than those typical in digital circuits. Once programmed, an EPROM can undergo erasure by exposure to a robust ultraviolet light source, such as a mercury-vapor lamp.

Distinctive Features of EPROMs: Recognizing the Transparent Window

EPROMs exhibit distinctive features, notably a transparent fused quartz (or, in later models, resin) window situated atop the package. Through this window, the silicon chip becomes visible, enabling exposure to ultraviolet light during the erasing process. This transparency is a hallmark characteristic of EPROMs.

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button
Close
Close