More advanced FDIR strategies often require a higher level of abstraction: monitoring multiple inputs, assessing plausibility, analyzing trends, and recording system behavior over time. Here, space-grade microcontrollers (MCUs) offer the ideal platform for intelligent, software-driven decision-making.

The MSP430FR5969-SP is specifically designed for low-power, space-constrained applications. It integrates ADCs, comparators, PWM outputs and voltage reference generation and many features more on a single chip, drastically reducing the need for discrete components. Its non-volatile FRAM memory is particularly well-suited for data logging, offering fast write cycles and high endurance. For example, using 20KB of the on-chip 64KB FRAM allows storage of up to 20,000 data points, which can be used for in-orbit software updates and behavioral tuning, fault analysis and root cause identification or post-mission review and optimization.

The TMS570LC4357-SEP dual-core lockstep MCU takes FDIR capabilities a step further. Originally developed for automotive safety systems such as Anti-lock Braking System (ABS) and power steering, this device was built from the ground up with ISO 26262 ASIL-D compliance in mind [3], [7].

Key device features include:

• Certified development process to minimize systematic fault probability [5] [6]
• Dual lock-step CPU architecture for real-time fault detection and response
• Comprehensive diagnostic coverage

These features provide the foundation for high-integrity fault response—even during mission-critical real-time operations. [8]

With 41 ADC channels, 64 GPIOs with timer and PWM capability, and multiple communication interfaces, the TMS570LC4357-SEP supports complex FDIR implementations. Its scalability is further enhanced by high-channel count devices like the AFE11612-SEP with 16 12-bit ADC channels, 12 digital-to-analog converter (DAC) channels, three temperature sensors and eight GPIOs. For example, adding two instances of AFE11612-SEP to the TMS570LC4357-SEP, as shown in Figure 4-1, enables a system with:

• 72 ADC Channels
• 32 DAC Channels
• Seven Complimentary PWM Outputs
• Six Enhanced Capture (eCAP) Modules
• Two Enhanced Quadrature Encoder Pulse (eQEP) Modules
• 64 GPIO with High-End Timer Modules for additional PWM outputs
• 16 Ext Interrupts/General-Purpose Input/Output (GPIO)
• Four Temp Sensor Inputs
• Two 2.5V-Reference Outputs
• 10/100Mbps Ethernet MAC
• Four Control Area Network (CAN) Controller
• Two Inter-Integrated Circuit (I2C) Modules
• Five Multi-buffered Serial Peripheral Interface (MibSPI)
• Four Universal Asynchronous Receiver/Transmitter (UART) Serial Communications Interface (SCI)

Figure 4-1 High-Channel Density Monitoring and Control System Based on TMS570LC4357-SEP and AFE11612-SEP

Whether deployed as a central controller for the entire satellite bus or as a localized FDIR unit on individual PCBs, the TMS570LC4357-SEP delivers high reliability and flexibility with near-instant fault detection performance.