 Jason
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00fbab6c9d
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Achieve full timing closure on xc7a100tcsg324-1 at 400 MHz (0 violations)
Complete FPGA timing closure across all clock domains after 9 iterative
Vivado builds. WNS improved from -48.325ns to +0.018ns (107,886 endpoints).
RTL fixes for 400 MHz timing:
- NCO: 6-stage pipeline with DSP48E1 phase accumulator, registered LUT
index (Fix D splits address decode from ROM read), distributed RAM
- CIC: explicit DSP48E1 PCOUT->PCIN cascade for 5 integrator stages,
CREG=1 on integrator_0 to eliminate fabric->DSP setup violation
- DDC: 400 MHz reset synchronizer (async-assert/sync-deassert),
active-high reset register for DSP48E1 RST ports, posedge output stage
- FIR: 5-stage binary adder tree pipeline (7-cycle latency)
- FFT: 5-cycle butterfly pipeline with registered twiddle index,
XPM_MEMORY_TDPRAM for data storage
- XDC: CDC false paths, async reset false paths, CIC comb multicycle paths
Final Build 9 timing (all MET):
adc_dco_p (400 MHz): WNS = +0.278ns
clk_100m (100 MHz): WNS = +0.018ns
clk_120m_dac (120 MHz): WNS = +0.992ns
ft601_clk_in (100 MHz): WNS = +5.229ns
Cross-domain (adc_dco_p->clk_100m): WNS = +7.105ns
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2026-03-16 15:02:35 +02:00 |
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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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c871281f1e
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Fix synthesis blockers in 9 RTL files for Vivado compatibility
Guard all $display/$error/$time calls with ifdef SIMULATION in:
- chirp_memory_loader_param.v (initial + always block debug prints)
- cic_decimator_4x_enhanced.v (5 saturation/overflow displays + monitor block)
- ddc_400m.v (FIR/baseband debug monitor block)
- fft_1024_inverse.v (IFFT config debug block)
- matched_filter_multi_segment.v (16 state machine displays + monitor)
- nco_400m_enhanced.v (initial block debug print)
- radar_receiver_final.v (frame/chirp counter displays)
Replace SystemVerilog constructs with Verilog-2001:
- usb_data_interface.v (typedef enum -> localparam + reg)
- usb_packet_analyzer.v (typedef enum -> localparam, output reg -> wire)
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2026-03-15 14:53:35 +02:00 |
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Jason
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76183e2e95
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Fix 6 RTL bugs in FPGA signal processing chain
- nco_400m_enhanced.v: Correct sine LUT values (3.7x quadrature error)
- ddc_400m.v: Fix wire forward-declaration (Verilog-2001 compliance)
- plfm_chirp_controller.v: Remove multi-driven chirp_counter (critical)
- radar_system_top.v: Fix CFAR wire-as-reg, connect chirp_counter to receiver
- radar_receiver_final.v: Promote chirp_counter to input port
All fixes verified with Icarus Verilog 13.0 testbenches (144/144 tests pass).
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2026-03-15 06:14:04 +02:00 |
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NawfalMotii79