Developing Game Accessories: The Design Challenges and Choosing an MCU
In this article, learn some of the design challenges facing game accessory development and considerations for selecting microcontroller units (MCUs) for game accessory designs.
The gaming industry is rapidly growing and evolving, at least in part due to continuous improvements in software and hardware. Increased access to high-bandwidth connections including 5G mobile services, better cloud infrastructure, unlimited data plans, and overall more feature-rich devices draw increasingly more people into gaming.
One key component of gaming that allows for individual engagement and customization is the auxiliary gaming accessories, including virtual reality and augmented reality (VR/AR) headsets, advanced controllers, and wireless headsets.
As customer expectations increase, designers often require powerful processors, fast random-access memory (RAM), and other design features that enable the development of these gaming accessories.
Virtual reality headsets and controllers. Image used courtesy of Pexels (Tima Miroshnichenko)
For these auxiliary gaming accessories, there are a few key properties and features that can be important for product designers to consider.
As one example, low latency, the time required to transmit data from one device to another, is a critical parameter for high-performance gaming and virtual reality applications.
For controllers, long latency in a gaming controller results in a poor user experience as the system responds slowly to user inputs. In a VR/AR headset, long latency can result in dizziness when the system doesn’t respond quickly enough to head movement.
With those thoughts in mind, this article examines the design challenges for developing gaming accessories and provides some guidelines for selecting MCUs for gaming accessory development, concluding with an examination of an example family of MCUs and resources for further research.
Gaming Accessory Design Challenges
When developing gaming accessories, it’s important to keep the particular context of the application in mind. While there are some general challenges to consider in the design of most gaming accessories (e.g., latency, battery life, data security, product longevity), different use cases will elicit different focal points during prototyping.
A personalized keyboard and controller system for home gaming may require a design approach focused on extending battery life, while an AR headset for an office setting might require more of a focus on low latency and data security.
Gaming controller in use. Image used courtesy of NXP
Unsurprisingly, there are tradeoffs for all design decisions. Engineers must always find a balance between the performance and battery life of all wireless gaming accessories. Higher performance means faster clock rates, more powerful processors, and more memory which typically comes at the expense of decreased runtime in battery-operated devices.
A fast central processing unit's (CPU) clock speeds, powerful on-chip peripherals, and co-processors help increase the overall responsiveness of wired and wireless accessories. Therefore, engineers should opt for a powerful MCU that's also efficient and offers power-saving modes.
As for scalability challenges and longevity, engineers may also need to use future-proof components. This could include support for over-the-air (OTA) firmware upgrades to support new features or operating modes. Having extra CPU horsepower and system memory can help accommodate these advances.
The Benefits of the Right MCU for Gaming Accessories
Let’s examine an example application: designing a wireless Bluetooth gaming headset. We can focus on several salient requirements of this use case:
- Processor performance
- Battery life
- Design footprint
As we review these design requirements, we will evaluate the features of the NXP LPC5500 series of Arm Cortex-M33-based MCUs (Figure 1) as an example product that could be used in these types of gaming products. In this context, we will take a look at the processor performance and the on-chip peripherals.
Figure 1. Block diagram for the LPC550X MCU family. Image used courtesy of NXP
High clock speeds, processing cores, and co-processors can help reduce problems such as input lag in gaming accessories. A higher CPU throughput allows the completion of more tasks in a given period which is critical for minimizing latency - both in communication and in response to user inputs.
NXP’s LPC5500 family features an Arm Cortex-M33 that can operate with a frequency of up to 96 MHz and includes an additional on-chip floating-point unit (FPU) that accelerates floating-point calculations. The high clocking frequency and hardware-accelerated floating-point operations can help reduce input lag and audio stutters in these types of headsets.
Large amounts of on-chip flash memory, in this case up to 256 KB, provide ample code storage for both product code development and future upgrades. A maximum of 96 KB of SRAM allows for complex data collection and processing. In the case of a wireless headset, this memory can be used for audio processing, noise reduction or cancellation, and processing of user inputs, potentially including voice commands.
Enhanced security options do not only protect user data. Modern on-chip security features can prevent unauthorized firmware tampering and detect data-integrity errors. Code encryption can prevent valuable IPs from getting stolen, and an encrypted transmission stream between a computer and a wireless accessory protects users against unauthorized access.
The benefits of a secure system also ripple out to the system as a whole and can make for a more efficient solution overall: on-chip hardware encryption and decryption engines reduce the load of the main CPU core and further speed up embedded applications.
To meet these demands, modern, complex system-on-chip products include a number of hardware security features.
For example, even the baseline NXP LPC5500 SoCs include Arm TrustZone® and a crypto co-processor that enables hardware acceleration to calculate asymmetric cryptographic algorithms like elliptic curve cryptography (ECC).
In addition, some of the LPC5500 models include significantly more security enhancements:
- Real-time encryption and decryption of flash memory data
- A dedicated AES-256 encryption/decryption engine
- Secure hash algorithm (SHA2) module that supports secure boot using a dedicated direct memory access (DMA) controller
- Physical unclonable function (PUF) using a dedicated SRAM to generate the unique silicon fingerprint. The PUF can generate, store, and reconstruct keys up to 4096 bits
- A 128-bit unique user identification (UUIC) device serial number
- A true random number generator (RNG) as opposed to a pseudo-random generator
Power Saving Features
For a wireless headset operating off battery power, efficient power management is crucial for increased operating life and longer standby times. Minimizing the power requirements can also mean the ability to use smaller batteries which, in turn, reduces size, weight, and cost.
An MCU optimized for wireless gaming applications should include multiple power modes and the ability to wake up from different types of inputs. At different power-down levels, the designer can trade off the wakeup time delay with the amount of power consumed during power down.
The NXP LPC5500 family of MCUs includes advanced power-management modes and an onboard power management unit (PMU).
The reduced power modes provide the designer with numerous options:
- Deep sleep with RAM retention
- Power-down with RAM and CPU retention
- Deep power-down with RAM retention
The PMU controls which system blocks continue operation and/or retain state during these power-down modes.
Design simplicity and small chip footprints allow engineers to build more cost-effective solutions by reducing the number of required external devices. Feature-rich MCUs can further help cut down the need for external devices. Reducing component count can allow reductions in size and weight which will support more ergonomic gaming accessories.
NXP’s LPC5500 family includes a number of digital and analog peripherals to support complex system designs. The digital serial interfaces support standard communication protocols like UART, I2C, and SPI. Dual DMA controllers provide fast, efficient data transfers to and from memory.
A multi-channel, 16-bit analog-to-digital converter (ADC) provides both single-ended and differential channels. In the wireless headset application, these could be used to monitor a user's microphone for voice capture and additional audio inputs for noise canceling. An on-chip temperature sensor can provide safety features to prevent overheating.
With packages as small as 7 mm x 7mm, engineers can leverage the full power of a fast MCU in small and ergonomic designs.
Summarizing Considerations for Game Accessory Design
When designing gaming accessories, engineers face various conflicting design challenges. High processing performance and high data throughput are necessary for increasing responsiveness and minimizing undesirable effects such as input lag in gaming accessories.
However, increased processing power and on-chip features often correlate to higher power usage and reductions in the effective runtime of battery-operated wireless accessories. If engineers want to achieve the best user experience, they should use a high-performing MCU that offers exceptional efficiency, such as the NXP LPC5500 series of general-purpose MCUs.
The design simplicity of a gaming-specific MCU helps engineers design more streamlined and cost-effective devices, and users benefit from more ergonomic, smaller, and lighter accessories. A rich set of on-chip peripherals, co-processors, and power-management circuitry can help decrease the number of required external components in a circuit. The reduced BOM and smaller physical PCB size help cut down the cost of an electronic design.
The NXP LPC550x/S0x product page contains more information, such as the available options for each model and exact specifications. The NXP gaming accessories page also contains examples of gaming peripherals. Various application notes can help engineers get started with using the LPC550x/S0x MCUs in their gaming-related projects.
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