Electronics Design

Group Assignment

In this group assignment, we used various test equipment to analyze the operation of a microcontroller circuit board. We began by verifying the power supply using a multimeter to ensure the board received a stable voltage. An oscilloscope was then used to check clock signals, confirming the correct operation of the system's timing components. Additionally, GPIO pins were observed to monitor their state changes, helping us understand the behavior of digital outputs.

My primary focus was on using the logic analyzer to examine communication protocols. I connected the analyzer to the microcontroller's I2C and UART lines, capturing real-time signals as data was transmitted between the microcontroller and peripherals. Using protocol decoding, I was able to interpret the transmitted data, checking for errors and validating the correct operation of communication interfaces. This step was crucial in debugging and ensuring that the microcontroller properly interacted with external devices.

Through this hands-on experience, I gained valuable insights into debugging embedded systems. The logic analyzer provided a deeper understanding of how data is structured and transmitted, reinforcing the importance of signal integrity and timing analysis in microcontroller-based circuits. This assignment helped us develop practical troubleshooting skills and a systematic approach to diagnosing electronic circuits.

Electronic Components

Electronic components are the elements of the circuit which help in its functioning the electrical circuit. Electronic components are the basic building blocks of an electronic circuit any electronic system or any electronic device. They can control the flow of electrons in an electronic system or electronic circuit.

Types of Electronic Components

An electrical circuit is an interconnection of Electronic Components. Based on their capability to generate energy these elements are classified into active or passive electronic Components.

Electronic Components are classified into two groups:

• Passive Components:

  Passive components are electronic devices that don't need an external power source to operate actively. They mainly resist, store, or control the flow of electric current or voltage in a circuit without actively amplifying or generating signals. For eg. Resistors, Capacitors, Transformers, Diodes, Thermistors, etc.

• Active components

  Active components are electronic devices that need an external power source to work. They actively control and manipulate the flow of electric current in a circuit. These components can amplify, switch, or generate electrical signals. For eg. Diode, Transistor, Integrated circuit, etc.

Connectors

Electronic connectors are devices that join electronic circuits. They are used in assembling, installing, and supplying power to electrical devices. Connectors are an important component of electronics used in industrial machinery, consumer products, communications, and home appliances.

For electronic connectors, gender is used to differentiate the mating connectors that match together in size, shape, and number of pins. The plug or male connector has pins for connecting to the female connector, which has a receptacle, jack, or socket for the male pins. The female connector has socket holes that contain terminals to wires, cables, or devices. The pins of the male plug are inserted into the female jack or socket to make electrical connections.

We explored different types of electronic connectors. The types of electronic connectors are:

• Header Connectors

  

  Cables made to connect to these pin headers are usually one of two types: individual wires with crimp connectors on them or ribbon cables with insulation displacement connectors.

  
• JST Connectors

  

  Japanese Solderless Terminal, also referred to as JST, is manufactured by a Japanese company of the same name. The JST system is primarily designed to bridge electrical connections or carry an electrical signal.

• Dupont

  

• Molex Connectors

  

• Barrel Connectors

  

• Terminal Connectors

  

• USB Connectors

  

Circuits

Pull Up Resistor

Pull-up resistors are resistors which are used to ensure that a wire is pulled to a high logical level in the absence of an input signal.

Digital logic circuits have three logic states: high, low and floating (or high impedance). The high-impedance state occurs when the pin is not pulled to a high or low logic level, but is left “floating" instead.

Without the pull-up resistor, the MCU’s input would be floating when the switch is open and pulled down to a logical low only when the switch is closed.

Pull Down Circuit

Pull-down resistors are resistors which are used to ensure that a wire is pulled to a low logical level in the absence of an input signal.

When the pushbutton is not pressed (open) the state of the pin will be logic LOW and when the pushbutton is pressed (closed) the state will be logical HIGH.

The pull-down resistor must have a larger resistance than the impedance of the logic circuit, or else it might be able to pull the voltage down by too much and the input voltage at the pin would remain at a constant logical low value - regardless of the switch position.

Voltage Divider Circuit

A voltage divider involves applying a voltage source across a series of two resistors. The primary purpose of this circuit is to scale down the input voltage to a lower value based on the ratio of the two resistors.

The poterntiometer is the most common application of a voltage divider circuit. A potentiometer usually has three external pins: two are the ends of the resistor and one is connected to the wiper arm.

A Level Shifter is another application of a voltage divider circuit,when a voltage needs to be leveled down. The most common scenario is when interfacing signals between a sensor and a microcontroller with two different voltage levels.

Voltage Regulator

To integrate a voltage regulator into a circuit properly, capacitors are added to filter out noise and stabilize the voltage. The first capacitor, a 0.33µF ceramic capacitor, is placed between the voltage source (e.g., a 9V battery) and the input pin of the regulator. This capacitor helps filter out unwanted noise or AC ripple from the power supply, ensuring that a clean DC voltage enters the regulator. By acting as a bypass capacitor, it diverts any high-frequency noise to ground, improving the efficiency of the regulator.

The second capacitor, a 0.1µF ceramic capacitor, is connected to the output pin of the regulator. This capacitor smooths out any remaining fluctuations or high-frequency noise in the regulated 5V output. While this may not be critical for simple applications like powering an LED, it becomes essential when supplying power to logic circuits or microcontrollers that require precise and stable voltages to function correctly. By following this setup, you ensure that the regulator operates efficiently and provides a clean, reliable power supply for your circuit.

EDA

Electronic Design Automation, or EDA, is a market segment consisting of software, hardware, and services with the collective goal of assisting in the definition, planning, design, implementation, verification, and subsequent manufacturing of semiconductor devices, or chips. Regarding the manufacturing of these devices, the primary providers of this service are semiconductor foundries, or fabs. These highly complex and costly facilities are either owned and operated by large, vertically integrated semiconductor companies or operated as independent, “pure-play” manufacturing service providers.

• Simulation tools take a description of a proposed circuit and predict its behavior before is it implemented.
• Design tools take a description of a proposed circuit function and assemble the collection of circuit elements that implement that function. This is both a logical process (assemble and connect the circuit elements) and a physical process (create the interconnected geometric shapes that will implement the circuit during manufacturing). These tools are delivered as a combination of fully automated and interactively guided capabilities.
• Verification tools examine either the logical or physical representation of the chip to determine if the resultant design is connected correctly and will deliver the required performance.

Some examples of EDA softwares are KiCad, Autodesk Eagle, Cadence, Altium,etc.

KiCad

KiCad is an open source software suite for Electronic Design Automation (EDA). The programs handle Schematic Capture, and PCB Layout with Gerber and IPC-2581 output. The suite runs on Windows, Linux and macOS and is licensed under GNU GPL v3.

I tried to explore KiCad for this week as my EDA tool because it is Open Source, packed with features and lots of shortcuts

KiCad's Schematic Editor supports everything from the most basic schematic to a complex hierarchical design with hundreds of sheets. Create your own custom symbols or use some of the thousands found in the official KiCad library.

KiCad's PCB Editor is approachable enough to make your first PCB design easy, and powerful enough for complex modern designs.

KiCad's 3D Viewer allows easy inspection of your PCB to check mechanical fit and to preview your finished product.

Essential Concepts for PCB Design

Designing a Printed Circuit Board (PCB) involves translating a circuit schematic into a physical layout while ensuring manufacturability, signal integrity, and reliability. Below are key elements to understand before starting a PCB design.

Schematic Design

• Schematic Symbol: A graphical representation of a component used in circuit diagrams (e.g., a resistor is a zigzag line, a capacitor is two parallel lines).

  

• Footprint: The actual physical layout of a component on the PCB, showing pad locations for soldering.
• Component Libraries: EDA tools provide predefined symbols and footprints (KiCad, Eagle, Altium, etc.), or they can be custom-made.

Traces & Routing

Traces are copper pathways on a PCB that electrically connect components. Proper routing ensures circuit reliability.

• Trace Width: Determines how much current a trace can carry. Wider traces are used for high-current paths.
• Trace Clearance: The minimum gap between two traces to prevent short circuits.
• Routing: Manual or autorouting strategies to optimize signal paths.

Design Rules and Checks

Ensuring a PCB follows proper electrical and manufacturing guidelines is crucial.

• DRC (Design Rule Check): Checks for trace width, clearance, via sizes, and other manufacturing constraints.
• ERC (Electrical Rule Check): Detects issues like unconnected nets, incorrect pin connections, and missing power connections.