The volatile fix in the companion PR (#118) makes the safe-mode blink loop
escapable in principle, but no firmware path existed to actually clear
system_emergency_state at runtime — hardware reset was the only exit, which
fires the IWDG and re-energises the PA rails that Emergency_Stop() cut.
This change adds a FAULT_ACK command (opcode 0x40): the host sends an exact
4-byte CDC packet [0x40, 0x00, 0x00, 0x00]; USBHandler detects it regardless
of USB state and sets fault_ack_received; the blink loop checks the flag each
250 ms iteration and clears system_emergency_state, allowing a controlled
operator-acknowledged recovery without triggering a watchdog reset.
Detection is guarded to exact 4-byte packets only. Scanning larger packets
for the subsequence would false-trigger on the IEEE 754 big-endian encoding
of 2.0 (0x4000000000000000), which starts with the same 4 bytes and can
appear in normal settings doubles.
FAULT_ACK is excluded from the FPGA opcode enum to preserve the
Python/Verilog bidirectional contract test; contract_parser.py reads the
new MCU_ONLY_OPCODES frozenset in radar_protocol.py to filter it.
7 new test vectors in test_gap3_fault_ack_clears_emergency.c cover:
detection, loop exit, loop hold without ack, settings false-positive
immunity, truncated packet, wrong opcode, and multi-iteration sequence.
Reported-by: shaun0927 (Junghwan) <https://github.com/shaun0927>
When an unknown signal is encountered, total is set to -1 but the
loop continues. Subsequent known signals add their widths to -1,
producing incorrect totals (e.g. -1 + 16 = 15 instead of -1).
This can mask genuine truncation bugs in status word packing.
Three-tier test orchestrator validates opcode maps, bit widths, packet
layouts, and round-trip correctness across FPGA RTL, Python GUI, and
STM32 firmware. Catches 3 real bugs:
- status_words[0] 37-bit truncation in both USB interfaces
- Python radar_mode readback at wrong bit position (bit 21 vs 24)
- RadarSettings.cpp buffer overread (min check 74 vs required 82)
29 tests: 24 pass, 5 xfail (documenting confirmed bugs).
4th CI job added: cross-layer-tests (Python + iverilog + cc).
Jason
NawfalMotii79
JunghwanNA