When choosing a microcontroller unit (MCU) for a new project, two key factors to consider are the peripheral sets offered and the vendor’s longevity. The peripherals available on the MCU determine what features can be implemented without external components. A vendor’s longevity gives an indication of future device availability and tool support. Selecting an MCU based on these factors can help ensure your project has the required functionality both now and in the future.
Assessing Peripheral Sets
The peripherals integrated into an MCU allow interfacing with external devices without additional components. For example, analog-to-digital converters (ADCs) enable reading analog sensors, while built-in USB handles connectivity to a PC. Here are some tips for assessing peripheral sets when selecting an MCU:
- Create a list of required peripherals based on your project’s needs – Know what external interfaces are needed before looking at device options.
- Compare peripheral sets across target MCU families – Tabulate or create a features matrix to see differences at a glance.
- Check if peripheral counts are sufficient – For interfacing multiple identical devices, verify there are enough peripherals.
- Confirm peripheral details match requirements – Resolution, speed, channels, etc. may vary.
- Consider future design evolution – Will more interfaces be added later? Plan ahead.
- Research availability of software drivers – Having vendor-supplied drivers can simplify development.
- Weigh fixed vs configurable peripherals – Fixed peripheral sets simplify design while configurable peripherals allow customization.
Getting the right peripheral set helps avoid costly external components and simplifies development. Focus on required interfaces first when evaluating MCU options to ensure critical needs are met.
Evaluating Vendor Longevity
An MCU vendor’s longevity gives an idea of future device and tool availability. Support longevity is important for long life and high volume products. Factors to research include:
- Company size and history – Larger and established vendors tend to have more staying power.
- Financial standing and backing – Check sources like annual reports for clues on vendor viability.
- Market share and industry presence – Vendors with large market shares tend to have more momentum.
- Commitment to the MCU market – Does the vendor rely on MCUs for a large part of revenue?
- Silicon manufacturing resources – Fabless vendors rely more on foundry viability.
- Internal vs external ARM cores – Architectural licensees integrate vendor’s own ARM core designs.
- Roadmap momentum – Steady new product introductions show continued investment.
Vendors that rank well across these metrics often make wise long term supplier choices. External market conditions can change quickly, but a vendor’s staying power gives confidence they will be there to support future product revisions.
MCU Selection Process
When selecting an MCU, consider both peripheral sets and vendor longevity together:
- Start with a list of target application requirements – Define must-have peripherals and interfaces needed.
- Research MCU vendors and identify those with strong longevity – Favor reliable long term suppliers.
- Compare vendor’s MCU families against peripheral requirements – Find optimal fit for needs.
- Create a decision matrix ranking MCU options – Weigh all evaluation criteria important to your project.
- Confirm chosen MCU has acceptable availability and lifecycle – Avoid soon to be obsolete devices.
- Consider consistent vendor or architecture usage – Can streamline future designs and reuse.
With mindful vendor and device selection, projects can reduce risk and maintain access to continued device supply and toolchain support. Leverage available research reports and consult industry experts when making MCU decisions. Careful selection considers both technical and business factors for success across the product lifecycle.
Example MCU Selection Comparison
As an example, consider selecting an MCU for a home automation controller project. Required interfaces are:
- Zigbee for wireless mesh networking with devices
- 10-channel ADC to read multiple sensors
- Multiple GPIO for device control
- Hardware crypto acceleration for security
- USB for configuration and firmware updates
After reviewing options, suitable choices include:
- Vendor A – XYZ12 MCU Family
- 8-channel ADC only, need external ADC
- Zigbee support via internal sub-GHz transceiver
- USB 2.0 device interface
- Hardware crypto engine
- Competitively priced MCU
- Vendor has 20+ year history in market
- Vendor B – ABC Pro MCU Family
- 16-channel ADC meets needs
- Requires external Zigbee transceiver
- USB 1.1 full speed interface
- No hardware crypto engine
- Higher cost MCU
- Stable vendor focused on industrial markets
In this example, Vendor A’s device has the best peripheral fit, while Vendor B ranks higher on longevity. The decision depends on the tradeoffs acceptable for the design constraints and goals.
Conclusion
Getting MCU selection right is important to avoid increased BOM cost, delayed development, or instability in long term support. Factoring in peripheral sets and vendor longevity when choosing microcontrollers results in designs that both meet technical needs and have robust supply chains. With ARM now a ubiquitous architecture in the embedded industry, ample options exist for finding the right blend of peripherals, architecture, and vendor stability. Taking the time upfront to thoroughly evaluate critical selection criteria will pay dividends across the entire product lifecycle.
