Embedded Systems Error Code
Systems & Devices
Embedded Systems
USAGEFAULT | Usage fault exception
Industry
Systems & Devices
Canonical
/systems/embedded-systems/error-codes/usagefault/
Last Updated
Feb 27, 2026
Summary
The CPU detected an illegal instruction, undefined state, or invalid execution condition.
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What This Code Means
Usage faults on Cortex‑M style systems can occur when the CPU executes an undefined instruction, divides by zero (if trapped), or enters an invalid state. It often points to corrupted code flow, stack issues, or jumping to an invalid address.
Where Users Usually See This Code
- Crash logs during runtime
- After firmware updates or new feature rollouts
Why This Code Appears
- Function pointer/callback points to invalid memory
- Stack corruption changed the return address
- Binary built for the wrong CPU/ABI settings
What Typically Happens Next
- Device resets or enters a fault handler loop
What This Code Is Not
- It is not a network or cloud service error
- It is not necessarily hardware failure
Troubleshooting Checklist
- □ Capture PC/LR values and stack trace if available
- □ Validate firmware build settings for the target MCU
- □ Review recent code changes around interrupts, callbacks, and stack usage
Notes And Edge Cases
UsageFault may be masked into HardFault if fault configuration differs by firmware.
Related Codes
8 links
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