 Jason
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c983a3c705
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Achieve timing closure: DSP48E1 pipelines, 4-stage NCO, 28-bit CIC, ASYNC_REG
Phase 0+ timing optimization (attempts #13-22 + implementation):
NCO (nco_400m_enhanced.v):
- 4-stage pipeline: DSP48E1 accumulate -> LUT read -> negate -> quadrant MUX
- DSP48E1 phase accumulator in P=P+C mode (eliminates 8-stage CARRY4 chain)
- Registered phase_inc_dithered to break cascaded 32-bit add path
DDC (ddc_400m.v):
- Direct DSP48E1 instantiation for I/Q mixers (AREG=1, BREG=1, MREG=1, PREG=1)
- CEP=1, RSTP=!reset_n for proper pipeline control
- 3-stage dsp_valid_pipe for PREG=1 latency
- Behavioral sim model under ifdef SIMULATION for Icarus compatibility
CIC (cic_decimator_4x_enhanced.v):
- 28-bit accumulators (was 36) per CIC width formula: 18 + 5*log2(4) = 28
- Removed integrator/comb saturation (CIC uses wrapping arithmetic by design)
- Pipelined output saturation comparison
CDC/ASYNC_REG:
- ASYNC_REG attribute on all CDC synchronizer registers (cdc_modules.v,
radar_system_top.v, usb_data_interface.v)
- Sync reset in generate blocks (cdc_modules.v)
Results: Vivado post-implementation WNS=+1.196ns, 0 failing endpoints,
850 LUTs (1.34%), 466 FFs (0.37%), 2 DSP48E1 (0.83%) on xc7a100t.
All testbenches pass: 241/244 (3 known stub failures).
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2026-03-16 01:02:07 +02:00 |
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Jason
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f5a3394f23
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Add 3 missing FPGA modules with enhanced testbenches (168/168 pass)
Implement the 3 modules identified as missing during repo audit:
- matched_filter_processing_chain: behavioral FFT-based pulse compression
- range_bin_decimator: 1024→64 bin decimation with 3 modes + start_bin
- radar_mode_controller: 4-mode beam/chirp controller
Wire radar_mode_controller into radar_receiver_final.v to drive the
previously-undriven use_long_chirp and mc_new_* signals.
Implement start_bin functionality in range_bin_decimator (was dead code
in the original interface contract — now skips N input bins before
decimation for region-of-interest selection).
Add comprehensive testbenches with Tier 1 confidence improvements:
- Golden reference co-simulation (Python FFT → hex → bin comparison)
- Saturation boundary tests (0x7FFF / 0x8000 extremes)
- Reset mid-operation recovery tests
- Valid-gap / stall handling tests
- Mode switching and counter persistence tests
- Accumulator overflow stress tests
Test counts: matched_filter 40/40, range_bin_decimator 55/55,
radar_mode_controller 73/73 — all passing with iverilog -g2001.
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2026-03-15 13:37:10 +02:00 |
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Jason
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558f49cd4a
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Add 8 Verilog testbenches with full coverage (144/144 pass)
Testbenches for: edge_detector (17), nco_400m (20), cic_decimator (14),
fir_lowpass (13), freq_matched_filter (14), ddc_400m full-chain (7),
chirp_controller (39), chirp_contract regression (20).
Includes CSV output data for waveform verification.
Add .gitignore to exclude VCD/VVP build artifacts.
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2026-03-15 06:14:11 +02:00 |
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