FPGA Reconfiguration with Rad-Hard MCU

Ken Obuszewski, VP of Business Development & Product, VORAGO Technologies

June 11, 2024

Advantages of Reconfiguring FPGAs with Radiation-Hardened Microcontroller Units

Field Programmable Gate Arrays (FPGAs) have been integral to many space missions due to their capability to adapt to mission changes for extended deployments, often 7 years or more.  This includes the ability to support evolving workloads and interfaces that are unique to space. Nonetheless, updating deployed FPGAs presents unique challenges such as a limited power envelope to program the FPGA and communication bandwidth to upload new code.

Reconfiguring space qualified FPGAs with radiation-hardened microcontroller units (rad-hard MCUs) offers a robust solution to these challenges. This blog explores the benefits of this approach.

What is an FPGA and How is it Used in Space?

An FPGA is a highly configurable digital integrated circuit, allowing the user to create custom logic designs. FPGAs can be programmed and re-programmed after manufacturing.

FPGAs are highly valued in space applications for their flexibility and ability to handle complex computations, data processing, and real-time control tasks. Their reconfigurable nature allows for adjustments and optimizations, making them ideal for space missions and other high-reliability scenarios.

Read more on the application of FPGAs in space.

Why Might You Need In-Flight Dynamic Reconfiguration of an FPGA?

A variety of factors may necessitate in-flight reconfiguration of FPGAs. Dynamic reconfiguration allows for adjustments to data rates, protocols, and other settings without affecting ongoing operations. This may be utilized to address:

• Changing mission requirements: As missions evolve, new functionality may be required, particularly on missions with lengthy deployment times. The ability to reconfigure the FPGA post-launch adds capabilities to the system and flexibility to the development timeline.

• Ongoing maintenance: Deployed systems require bug fixes and security updates. With in-flight reconfiguration, features can be added or completed, bugs and security issues corrected after launch of the spacecraft, and multiple mission modes can be supported.

• Error correction: Issues such as extreme weather and solar storms in space can cause errors such as single-event upset (SEU) and single-event latch-up (SEL).

• Performance optimization: Use cases such as observation and image processing require continuous optimization of algorithms or processes to maximize performance.

Traditional Challenges of Reconfiguring FPGAs in Space

• Radiation Environment: Extreme radiation encountered in space often requires redundant FPGAs to ensure the integrity of the reconfiguration. Also, it is necessary to ensure that the bitstream and hardware used for reconfiguration are not impacted by radiation.

• Limited Communication Bandwidth: Reprogramming from Earth requires sending new configuration data through limited bandwidth communication channels. This can be a time-consuming process, especially for large bitstreams.

• Power Constraints: Reprogramming an FPGA can be a power-intensive process, which can interfere with other critical systems. Managing power consumption is also critical to staying within thermal budgets.

What is the Relationship Between FPGAs and Microcontrollers?

FPGAs and microcontrollers are both integral components in embedded systems, but they serve different purposes and have distinct characteristics.

Microcontrollers provide a cost-efficient, easy-to-use platform for control and communication-oriented applications, while FPGAs offer customizable hardware solutions for data-intensive applications with high performance requirements.

Microcontrollers and FPGAs can be used together to create powerful and flexible embedded systems, and often coexist in advanced electronic systems. This synergy enhances the overall capability and efficiency of the system.

Read more about when to use an FPGA vs microcontroller.

Why Reconfigure FPGA with Rad-Hard MCU?

Radiation-hardened electronics, including radiation-hardened microcontrollers, are specially designed to withstand high levels of radiation exposure, providing reliability and resilience in high-radiation environments, such as Space.

Utilizing a rad-hard MCU for FPGA reconfiguration offers several benefits:

• Maximum Resilience: Rad hard MCUs are designed to withstand radiation effects including total ionizing dose (TID) and single event upset (SEU). Use of a rad hard MCU in conjunction with the FPGA provides system-level redundancy to avoid and mitigate radiation-induced errors. While the FPGA may be prone to radiation effects, the rad-hard MCU will be able to withstand radiation and ensure uptime during reconfiguration, maximizing the probability of success on the first try.

• Enhanced reliability: The MCU is utilized to ensure the integrity of the bitstream and manage any necessary error handling. The MCU adds reliability to the system as it can detect a corrupted FPGA bitstream, and the correct bitstream can be re-uploaded, or a backup configuration can be used instead. The MCU even has the potential to correct the bitstream in real time.

• Adaptability: Allows for on-the-fly adjustments to system operations, such as memory scrubbing, to address unforeseen issues that arise during operation. The low power nature of the MCU allows for frequent reconfiguration while maintaining thermal and power budget constraints, and the use of a rad-hard MCU eliminates the need for multiple rounds of reconfiguration per instance.

• Autonomy: The MCU allows the FPGA configuration to be managed locally.  This includes local storage of the bitstreams, and management of the reprogramming processes. This removes the need for FPGA redundancy.

For information on different rad-hard MCUs and their specific applications, explore our selection guide for rad-hard MCUs.

VORAGO Rad-Hard MCUs Enable FPGA Reconfiguration

VORAGO’s rad-hard ARM Cortex®-based MCUs with patented HARDSIL® radiation hardening technology are specifically targeted at space and defense applications. Increasingly, VORAGO MCUs are being used to reconfigure space-grade FPGAs in orbit.