Lock in the four structural invariants of the 2-frame confirmation
debounce: local variable captures DIG_6 read, static prev initialized
to false (matches FPGA boot), outerAgc.enabled gated by now==prev
guard, and prev advances each frame. Prevents a naive refactor from
silently removing the glitch protection.
Credit: joyshmitz review on PR #93.
Resolve cross-layer AGC control mismatch where opcode 0x28 only
controlled the FPGA inner-loop AGC but the STM32 outer-loop AGC
(ADAR1000_AGC) ran independently with its own enable state.
FPGA: Drive gpio_dig6 from host_agc_enable instead of tied low,
making the FPGA register the single source of truth for AGC state.
MCU: Change ADAR1000_AGC constructor default from enabled(true) to
enabled(false) so boot state matches FPGA reset default (AGC off).
Read DIG_6 GPIO every frame with 2-frame confirmation debounce to
sync outerAgc.enabled — prevents single-sample glitch from causing
spurious AGC state transitions.
Tests: Update MCU unit tests for new default, add 6 cross-layer
contract tests verifying the FPGA-MCU-GUI AGC invariant chain.
Silently skipping Tier 2/3 tests in CI defeats the purpose of running
them. Add a GITHUB_ACTIONS guard that raises RuntimeError at module
load if iverilog or C++ compiler is not found, preventing false-green
CI results from skipped tests.
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.
The default IVERILOG and VVP paths were hardcoded to macOS Homebrew
locations (/opt/homebrew/bin/iverilog). On Ubuntu CI runners, apt
installs iverilog to /usr/bin/, so the Path.exists() check returns
False and all Tier 2 Verilog cosim tests are silently skipped.
Change defaults to bare command names so the existing which-based
fallback at line 57-58 discovers the binary via PATH on any platform.
Bug 1 (FPGA): status_words[0] was 37 bits (8+3+2+5+3+16), silently
truncated to 32. Restructured to {0xFF, mode[1:0], stream[2:0],
3'b000, threshold[15:0]} = 32 bits exactly. Fixed in both
usb_data_interface_ft2232h.v and usb_data_interface.v.
Bug 2 (Python): radar_mode extracted at bit 21 but was actually at
bit 24 after truncation — always returned 0. Updated shift/mask in
parse_status_packet() to match new layout (mode>>22, stream>>19).
Bug 3 (STM32): parseFromUSB() minimum size check was 74 bytes but
9 doubles + uint32 + markers = 82 bytes. Buffer overread on last
fields when 74-81 bytes passed.
All 166 tests pass (29 cross-layer, 92 GUI, 20 MCU, 25 FPGA).
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
JunghwanNA