Microcontroller PCB design is slightly different from conventional boards; there are numerous parameters to take care of and various design rules to adhere to. Use this to learn the process of creating one. Let’s begin with the meaning of this PCB type.
What is a Microcontroller Board?
A microcontroller (MCU) board is a programmable PCB with one or more microcontrollers. The MCU is a single-chip computer. It acts as the board’s brain and contains these main parts: a central processing unit, memory, and I/O peripherals.
These circuit boards are simple to fabricate. They also cost less than microprocessors, plus you can use them in virtually any project, from those involving simple controls to those requiring computations.
MCU PCBs work with embedded electronic systems and devices. They help perform software-controlled functions. For example, you can interface them with sensors to react to conditions or place them in a device to control its operation.
The PCB microcontroller can be a simple board with only a few components or a complicated type with many electrical interconnections and layers; it depends on the particular project and the required control level.
Microcontroller PCB Design
A microcontroller circuit board starts with design preparation. To create it, you determine the required controller type and the various components. Your project requirements dictate the type of PCB to make.
For instance, a straightforward MCU with only a few Kbs of memory and a single I/O input may suffice if the application is a timed function. However, it may not be if the project requires complex logic.
To design an MCU PCB, you must understand digital and analog electronics. It’s also necessary that you know how to work with PCB design software and have a grasp of the board requirements.
But what if you do not have these skills? You can have one created for you. Many manufacturers provide circuit board design and fabrication services.
Alternatively, you may do it and send it to the manufacturer for production. Learn how to design PCB microcontroller boards in the next section.
How to Design a Microcontroller PCB
You’re now conversant with this circuit board type, so let’s begin the design process. It involves creating the schematics and layout before sending the production file to your manufacturer. Follow these steps.
Step 1: Block Diagram
The microcontroller board design process starts with a block diagram or a representation of the board’s architecture and functionality. Indicate the board parts in the diagram, their purpose, and connections. In a nutshell, ensure you establish the following:
- The required processing power; this will later determine the controller type to use
- Power requirements, including maximum and minimum voltage levels
- Thermal management requirements
- EMI mitigation needs
- The types of inputs and outputs or communication protocols
Use the above requirements to choose the various parts, such as power and heat management circuits and components, communication interfaces, sensors, etc.
Step 2: Microcontroller Selection
Microcontrollers are available in many different types depending on the required function. Select your MCU type strictly based on the project requirements. Your options will mainly include these types.
- AVR MCU
- PIC MCU
- ARM MCU
- 8051 MCU
- MSP MCU
Other specifics include the bit rate (16, 32, 64), architecture type (RISC, CISC), memory type (on-chip, off-chip), and chip Type (SIP, DIP, QFP, SIP, PGA, BGA, TQFP). ARM-based MCUs are the most popular. They suit many applications.
Step 3: Microcontroller PCB Design Schematics
After identifying the controller type, it’s time to create the schematics. The schematic drawing is a digital representation of the entire circuit. This step requires a program, such as KiCad, Altium, etc. Include the following:
- The various parts and their names (the controller IC, USB and programming connectors, voltage regulator, capacitors)
- Component values and ratings
- Components or parts numbers
Start by placing active components. Some circuits are too large and complex to fit in one sheet. Consider creating subcircuits first. You can then join these later. It makes the task easier. Use the diagram to prepare the BOM or bill of materials.
Step 4: Microcontroller PCB Design Layout
With the schematic drawing completed, you can now create the layout. This part of the microcontroller PCB design process requires arranging the components and routing the traces. Ensure the following when placing components.
Optimize the routing process to minimize signal loss from EMI or crosstalk. You now have the PCB layout or a 3D representation of the components. The next stage is testing it for functionality and ensuring zero omissions during the design process.
Step 5: Design Verification
Next, verify your design by running an automatic process. Your microcontroller PCB layout software will usually have this function. It will match the schematics to the layout and check if the design follows the required rules.
Rework the design if a problem crops up. You do not want to proceed with a defective circuitry. Your board may not work as intended.
Step 6: Production Files Generation
With everything confirmed, it’s time to send your microcontroller PCB design to the fabricator. But the file is still in the proprietary format, and you need to convert it into the industry-standard format called Gerber file.
The Gerber file will contain the different board layers. They include solder paste, silkscreen, and assembly layer files.
Other necessary files before production are assembly or pick-and-place files for component assembly and the drilling file for the machine that will create holes.
Microcontroller PCB Design Guidelines
The microcontroller on a PCB means the board carries analog and digital signals, including the high-frequency types. As such, you must optimize its design to ensure signal integrity, proper power distribution, and heat management, among other requirements. These tips should help you accomplish that.
1. Select the correct controller type based on your specific project. Choose a complex type if your application requires higher processing and vice versa.
2. Separate analog and digital or high-speed lines when routing traces, traces. It will help avoid signal degradation.
3. Shorten the traces. Keep them straight, especially if making the circuit for a high-power or high-frequency PCB microcontroller device.
4. Place heat-generating parts near heat sinks and other heat dissipaters to prevent thermal problems. You may locate them in ventilated regions instead.
5. Separate signal layers with ground planes, especially if designing an RF circuit, and reduce the number of vias to minimize interference.
Conclusion
In this guide, you learned the microcontroller PCB design steps. MCU boards have special considerations that require more input than conventional boards. The steps and guidelines in this article explain the dos and don’ts when making this board type. Use them to ensure success in creating yours and the success of your project.