RP2350 Microcontroller Family - Simplifying Complex Choices in Embedded Systems

The RP2350 microcontroller family by Raspberry Pi introduces new layers of complexity for embedded systems. With significant advancements in processing power, security, and energy efficiency, it offers developers more powerful and versatile options than its predecessor, the RP2040. However, the increased complexity and various configurations available in the RP2350 series can make it challenging for electronics developers to determine which solution best suits their design needs.

Navigating the Complexity of the RP2350 Family

The RP2350 family comes with several variations, each designed to address different technical requirements.

Dual-Core Processor Architecture

The RP2350 family gives developers a choice between two processor architectures:

1. Dual-core Arm Cortex-M33: Known for high efficiency and security features, the Cortex-M33 cores provide a strong performance-to-power consumption ratio. Running at 150 MHz, these cores deliver better computational power than the RP2040’s Cortex-M0+ cores, which are limited to 133 MHz. This makes the RP2350 ideal for more demanding tasks, such as real-time control and data processing.

2. Dual-core RISC-V Hazard3: For those who prefer an open-source ecosystem, the RP2350 offers an alternative with RISC-V cores, also clocked at 150 MHz. This allows developers to leverage the growing RISC-V community and tools, enabling greater flexibility in custom applications.

Memory and Storage

• On-chip SRAM: With 520 KB of SRAM, the RP2350 provides ample memory for applications requiring multiple threads or real-time data processing. This nearly doubles the memory available in the RP2040 (264 KB), making it suitable for more complex systems.

• Flash Support: For applications requiring larger programs or data storage, the RP2350 supports up to 16 MB of external QSPI flash. The RP2354 variant includes 2 MB of internal flash, eliminating the need for an external flash chip in some designs.

GPIO and Peripheral Connectivity

• GPIO: The RP2350A comes with 30 GPIO pins, while the RP2350B has 48 GPIO pins. These pins support multiple communication protocols, including UART, SPI, and I2C. This versatility makes the RP2350 suitable for interfacing with a wide variety of sensors, actuators, and other peripherals commonly used in embedded systems.

• ADC (Analog-to-Digital Converters): The RP2350B includes up to 8 ADC-capable pins, providing enhanced functionality for reading analog inputs like sensors, making it an attractive option for IoT applications.

Power Management 

• The RP2350 features an integrated switching voltage regulator, which can handle up to 200 mA of current. This is a significant upgrade from the 100 mA linear regulator in the RP2040, improving power efficiency at higher loads. Additionally, the RP2350 supports low-power states, making it suitable for energy-conscious applications like battery-powered IoT devices.

Security Features

• Arm TrustZone technology is integrated into the Cortex-M33 cores, providing hardware-based isolation between trusted and untrusted code execution. This feature is critical for applications where security is paramount, such as IoT devices that handle sensitive data.

• The RP2350 also includes SHA-256 hardware acceleration and glitch detection to protect against physical attacks, making it a robust choice for applications in industrial control, finance, or healthcare where data integrity and security are key concerns.

Hardware Overview of the RP2350 Family Microcontrollers

The RP2350 series represents a leap forward in microcontroller design, offering powerful options for embedded systems and IoT applications. The RP2350 family comes in four variants:

• RP2350A: 30 GPIO pins in a compact 7 × 7 mm QFN-60 package

• RP2350B: 48 GPIO pins in a larger 10 × 10 mm QFN-80 package

• RP2354A: RP2350A model with an additional 2 MB QSPI NOR flash

• RP2354B: RP2350B model with an additional 2 MB QSPI NOR flash

Figure 1: Picture of a RP2350 Microcontroller in its QFN-60 format¹

While these options expand the possibilities for electronics developers, they also introduce added complexity, as each variation provides unique performance, security, and energy profiles. Selecting the optimal model requires an understanding not only of the technical capabilities but also of how each model fits within the project’s broader design constraints. For component manufacturers, ensuring that their parts are adopted in this competitive and complex environment demands a solution that simplifies the decision-making process for engineers.

Key Factors to Consider When Developing Hardware with the RP2350

When developing hardware with the RP2350 microcontrollers, several important factors need to be carefully considered:

Power Supply Design

The switching voltage regulator in the RP2350 requires careful component selection and PCB layout to ensure stable operation. The layout of the regulator must minimize noise and interference, and the use of decoupling capacitors is essential to filter power supply noise. Additionally, ensuring proper ground return paths for high-current traces is critical for preventing voltage drops and maintaining signal integrity.

Memory Configuration

If you're using the RP2350 without internal flash, selecting the right Quad-SPI flash memory and carefully routing the QSPI signals on the PCB are essential to ensure reliable program execution. The use of short, direct traces between the RP2350 and the flash chip helps minimize signal degradation, ensuring reliable communication at high clock speeds.

GPIO and Peripheral Considerations

Careful planning is required to allocate the GPIO pins efficiently. If you're using multiple peripherals (e.g., SPI, I2C, and ADC channels), it’s essential to balance the available GPIOs, especially when designing with the QFN-60 variant, which has fewer pins. For high-frequency communication protocols like USB, maintaining signal integrity through careful PCB trace routing is critical.

Security Implementation

For applications requiring secure data handling, leveraging the TrustZone features in the Cortex-M33 cores is key. Developers should implement secure boot processes and take advantage of hardware-based encryption acceleration to protect sensitive data and firmware.

Debugging and Development Tools

The RP2350 offers support for SWD (Serial Wire Debug), which is essential for debugging and development. Using the optional JST debug connector can make this process more convenient, especially for prototype development and testing.

The CELUS Design Platform and CUBOs - Simplifying Adoption of Complex Components

This is where the CELUS Design Platform and its CUBOs come into play. CUBOs, or “Digital Datasheets”, are interactive representations of circuits on the CELUS platform that go beyond traditional datasheets by providing structured, searchable information. When component manufacturers choose to offer their parts as CUBOs, they allow developers to explore complex specifications quickly and confidently, reducing the friction typically associated with component selection.

Using the RP2350 family as an example, CUBOs can break down intricate details, such as processing cores, memory configurations, and interface selection, into easily digestible sections. Each CUBO provides engineers with all essential specifications, performance data, and connections , enabling them to assess, compare, and implement components more efficiently. For component manufacturers, presenting their solutions as CUBOs helps their products stand out in a crowded market, where ease of understanding and accessibility can be key factors in component adoption.

Key Benefits for Component Manufacturers 

By working with CELUS to represent their components as CUBOs, component manufacturers can enjoy several advantages:

• Enhanced Accessibility: Unlike traditional datasheets, CUBOs are designed to fit seamlessly into an engineer’s workflow, offering an intuitive, interactive format that helps developers quickly understand complex components.

• Increased Adoption: As engineers are more likely to select components that are both available and easy to implement, having parts presented as CUBOs increases their appeal. CUBOs allow engineers to navigate specifications, evaluate configurations, and access design resources effortlessly, making it more likely that a component will be integrated into a final design.

• Effective Communication of Features: Components like the RP2350 family, with their array of security and performance options, may initially seem overwhelming to developers. CUBOs help distill these complexities into clear, concise representations that engineers can quickly interpret, facilitating better-informed decisions.

RP2350 Now Available in CELUS Design Studio

Below are examples of how the RP2350 CUBOs appear on the CELUS platform. These CUBOs showcase the intricate details of each RP2350 variant, helping developers make informed choices by highlighting key specifications, connections, and functionality.

Figure 2: The RP2350B CUBO highlights its dual-core setup and optimized memory structure, allowing developers to gauge its suitability for high-performance applications.

Figure 3: The RP2354A CUBO displays critical specifications like built-in flash memory and GPIO configurations, making it easy for developers to assess its fit for diverse embedded projects.

With the RP2350 family now accessible in the CELUS Design Studio, developers have a powerful tool at their disposal to simplify complex design decisions. CELUS enables developers to convert technical requirements into schematics quickly, taking full advantage of the RP2350’s capabilities. For component manufacturers, turning components into CUBOs on the CELUS platform not only improves component visibility but also streamlines the design process for engineers, making the components more attractive and effective in real-world applications.

In a world where component choice is driven by both availability and ease of implementation, presenting complex solutions like the RP2350 as CUBOs gives component manufacturers a competitive edge, facilitating faster adoption and deeper market penetration.

[1] Raspberry Pi Documentation. Retrieved 2 October 2024.