Drop the chirp-v1 1-bit use_long_chirp memory loader and its 6 .mem files;
introduce chirp_reference_rom — wave_sel-native, single 8192x16 BRAM array
per Q15 lane, 4-region init (SHORT, MEDIUM, LONG seg0/seg1) loaded from the
PR-B mem files. Same 1-clk read latency as the legacy module so the RX-B
autocorrelation alignment fix carries through unchanged.
Receiver-side wave_sel shim added in radar_receiver_final.v:
wire [1:0] wave_sel = use_long_chirp ? RP_WAVE_LONG : RP_WAVE_SHORT;
This is a 1-line transitional bridge while radar_mode_controller still
emits 1-bit use_long_chirp; PR-D deletes the shim and wires chirp_scheduler
straight through. MEDIUM is loaded into the ROM but unreachable through
the production path until PR-D.
BRAM cost: 8 RAMB18 (was 6 in chirp-v1). +2 BRAM is the cost of adding
MEDIUM to the waveform set; not avoidable.
Files added:
- chirp_reference_rom.v
Files removed:
- chirp_memory_loader_param.v
- long_chirp_seg{0,1}_{i,q}.mem (4 files)
- short_chirp_{i,q}.mem (2 files)
- tb/cosim/validate_mem_files.py (legacy file-set validator; replaced by
gen_chirp_mem.py's internal verify_phase_match)
- tb/cosim/analyze_short_chirp_mismatch.py (one-shot tool from the
chirp-v1 TX-I investigation; finding incorporated, references the
deleted short_chirp_*.mem files)
Files updated for module rename:
- radar_receiver_final.v — instance, comments, wave_sel shim
- radar_mode_controller.v — header comment
- matched_filter_processing_chain.v — header comment
- scripts/200t/build_200t.tcl — explicit RTL list
- run_regression.sh — 5 spots
- tb/tb_rxb_fullchain_latency.v — instance, wave_sel shim, mem filenames,
SHORT_LEN 50 → 100 (1 µs at 100 MHz)
- tb/tb_system_e2e.v — header comment
Verification:
- chirp_reference_rom standalone iverilog compile: clean
- Full receiver chain compile (21 RTL files): clean
- tb_rxb_fullchain_latency runs end-to-end with new ROM + new mem files
+ 100-sample SHORT chirp; autocorrelation peak at bin 0, peak |I|+|Q|
= 15115. Confirms 1-clk ROM read latency is preserved and the RX-B
direct-wire-with-1-FF alignment still holds.
- 50T build script (scripts/50t/build_50t.tcl) uses glob *.v — no edit
needed; it picks up the new file automatically.
latency_buffer.v has had zero non-tb instantiations since RX-B (2026-04-23)
replaced its hookup in radar_receiver_final with a 1-FF alignment register.
The module was being kept "for potential future use" — exactly the kind of
dead weight the codebase does not need. Deleted, along with all build /
test infrastructure that dragged it along:
- 9_Firmware/9_2_FPGA/latency_buffer.v
- 9_Firmware/9_2_FPGA/tb/tb_latency_buffer.v
- run_regression.sh: removed from RTL_FILES and RECEIVER_RTL
- scripts/200t/build_200t.tcl: removed from synthesis source list
- tb/tb_system_e2e.v: removed from header compile-string example
- tb/cosim/validate_mem_files.py: deleted test_latency_buffer() (~75 lines),
its call site, and the corresponding entry in the module docstring
Historical RX-B comments referencing latency_buffer in radar_receiver_final.v,
tb_rxb_fullchain_latency.v, and tb_rxb_latency_measure.v are kept — they
explain WHY the module was removed, which is still useful design archaeology.
Two doc-only housekeeping touches bundled in:
- plfm_chirp_controller.v: replaced two empty "CRITICAL FIX: Generate
valid signal" labels at LONG_CHIRP and SHORT_CHIRP with one shared
chirp_valid policy comment block above LONG_CHIRP that explains the
actual rationale (downstream FIFO underrun on trailing samples).
- v7/models.py: replaced the "range_resolution and velocity_resolution
should be calibrated" docstring (sounded like an open TODO but was a
documented placeholder) with a clear pointer to the GUI-C3 fix in
workers.py:RadarDataWorker so future readers know the live path
derives correct values from WaveformConfig.
FPGA quick regression unchanged: 28/29 (1 fail is the unrelated iverilog/
Xilinx-IP RX-NEW-3 gap). GUI suite 180/180. Ruff clean.
Replaces the in-house iterative fft_engine.v in the matched-filter chain
with the Pipelined Streaming Xilinx FFT IP, closing RX-NEW-3 (FFT chain
~11x too slow vs PRI budget).
Components:
* ip/xfft_2048_ip/xfft_2048_ip.xci — committed IP definition
(16-bit fixed point, BFP scaling, convergent rounding, natural order,
pipelined-streaming, BRAM data/reorder/phase factors). Vivado
regenerates .dcp / sim-netlist from this on each build.
* scripts/50t/gen_xfft_2048_ip.tcl — IP-Catalog generation script
* scripts/50t/run_xfft_xsim.sh — XSim batch runner for tb_xfft_2048_xsim
* xfft_2048.v — AXI-Stream wrapper. FFT_USE_XILINX_IP define routes to
real LogiCORE for synth/XSim; falls back to fft_engine batched
one-shot for iverilog (unit coverage only).
* fft_engine_axi_bridge.v — exposes legacy fft_engine port surface on
top of the xfft_2048 AXI wrapper, so the chain swap is a 1-line
module-name change.
* matched_filter_processing_chain.v — fft_engine -> fft_engine_axi_bridge
* scripts/50t/build_50t.tcl — read_ip + generate_target + synth_ip;
adds FFT_USE_XILINX_IP to verilog defines.
* tb/tb_xfft_2048_xsim.v — XSim verification (DC, impulse, tone bin 128).
All 5 assertions PASS on remote with the real IP; tuser=0x0a (BLK_EXP=10)
confirms BFP scaling working.
Local iverilog regression: 32/34 PASS — identical to baseline. Same two
RX-NEW-3 failures (Receiver Integration, Matched Filter Chain) — these
only resolve in remote XSim with the real IP, since iverilog uses the
fft_engine fallback inside xfft_2048 (~150K cycles/pass, not the
~2200-cycle Pipelined Streaming throughput). MF cosim 4/4 PASS confirms
bridge bit-exact in fallback mode.
Pending: remote XSim of tb_radar_receiver_final to demonstrate Doppler
frames produced within PRI budget; remote synth to confirm DSP/timing
post-IP.
C4 is an SRCC pin (IS_CLK_CAPABLE=1, IS_MASTER=0 in the Vivado device
model), not an MRCC as earlier comments claimed. SRCC cannot drive BUFG
through dedicated routing, so the previous CLOCK_DEDICATED_ROUTE=FALSE
override forced fabric routing and burned ~5 ns on the ft_clkout path
(WNS -5.362 ns in the d36a4c9 build).
Swap to BUFIO + BUFR for USB_MODE=1 (50T/FT2232H): SRCC → BUFIO → BUFR
is the standard 7-series path for regional clock distribution. All
ft_clkout-domain logic (FT2232H FSM, toggle CDCs, USB FIFO flops) is
contained in bank 35 / one clock region, so regional distribution is
sufficient. USB_MODE=0 (200T/FT601) keeps the BUFG because D17 is a
proper MRCC pin.
Removed CLOCK_DEDICATED_ROUTE=FALSE from both the XDC and the build
script — no longer needed with dedicated BUFIO/BUFR routing.
- Add set_false_path -hold for source-synchronous ADC IDDR paths in
adc_clk_mmcm.xdc (eliminates 8 hold violations from build 12)
- Add DDR falling-edge input delay constraints to xc7a50t_ftg256.xdc
(parity with 200T XDC)
- Reorganize scripts/ into target subdirectories: 50t/, 200t/, te0712/,
te0713/, utils/ so users can run the correct build for their hardware
- Delete obsolete build scripts (build17-20) superseded by build_50t/200t
- Update project_root paths in all moved scripts (.. -> ../..)
The XC7A50T-FTG256 has only 69 usable IO pins but radar_system_top
declares 182 port bits. Previous attempts to remove unconstrained
ports via TCL caused opt_design to cascade-remove all driving logic.
New approach: radar_system_top_50t.v is a thin wrapper that:
- Exposes only the 64 physically-connected ports (ADC, DAC, SPI, clocks)
- Instantiates radar_system_top internally with full logic preserved
- Ties off unused inputs (FT601 bus, ext trigger) to safe defaults
- Leaves unused outputs internally connected (no IOBs created)
Updated build_50t_test.tcl to use radar_system_top_50t as top module
and removed the now-unnecessary port removal TCL code.
remove_port fails on connected ports with [Coretcl 2-28]. Add
disconnect_net step before remove_port to properly detach the
port from its driving/driven nets in the synthesized netlist.
The 50T FTG256 has only 69 usable IO pins but the RTL declares 182 port
bits. launch_runs spawns a child process that cannot remove ports.
Switch to direct opt_design/place_design/route_design flow so we can
remove 118 unconstrained ports (FT601 USB, dac_clk, status/debug) from
the netlist before placement, avoiding [Place 30-58] IO overflow.
The placer enforces a single VCCO per bank. LVDS_25 forces Bank 14
to VCCO=2.5V, which conflicts with LVCMOS33 (needs 3.3V). Changing
adc_pwdn to LVCMOS25 resolves [Place 30-372] bank incompatibility.
The AD9484 PWDN pin has CMOS-level thresholds (~0.8V), so 2.5V
output drives it correctly.
set_property SEVERITY in the parent Vivado process does not propagate
to the child process spawned by launch_runs. Write a drc_waivers_50t.tcl
hook and attach it via STEPS.OPT_DESIGN.TCL.PRE so BIVC-1, NSTD-1,
and UCIO-1 are demoted to warnings inside the impl_1 run context.
Three issues prevented the 50T (FTG256) build from completing:
1. LVDS standard: LVDS_33 and LVDS do not exist on 7-series HR banks.
Changed to LVDS_25 (the only valid differential input standard).
IBUFDS inputs are VCCO-independent, so LVDS_25 works correctly even
with Bank 14 VCCO=3.3V.
2. BIVC-1 DRC: Bank 14 has LVDS_25 (needs 2.5V) and LVCMOS33 adc_pwdn
(needs 3.3V). Since all LVDS ports are inputs (IBUFDS only), the
voltage conflict does not affect functionality. Demoted to warning.
3. Pin overflow: 113 ports vs 69 available FTG256 pins. The 118
unconstrained port bits (FT601 unwired, status/debug unrouted,
dac_clk unconnected) cause NSTD-1/UCIO-1 DRC errors. Demoted to
warnings since these ports have no physical connections on this board.
Also added: CFGBVS/CONFIG_VOLTAGE settings, build_50t_test.tcl to repo.
Build scripts (17-21): STATS.WNS/TNS/WHS/THS/TPWS from get_property can
return empty strings in Vivado 2025.2 after write_bitstream auto-launch.
Wrap in catch with N/A fallback. Guard all expr delta calculations and
signoff comparisons with [string is double -strict] checks.
XDC (xc7a50t_ftg256): Fix PLIO-9 by moving clk_120m_dac from C13 (N-type)
to D13 (P-type MRCC) — clock inputs require P-type MRCC pin. Fix BIVC-1 by
disabling DIFF_TERM on Bank 14 LVDS pairs to resolve VCCO conflict with
single-ended adc_pwdn (LVCMOS33) on T5 — requires external termination.
- Escape [extra] → \[extra\] to prevent TCL interpreting it as a command
(Vivado resolved 'extra' to 'extract_files' causing ERROR [Common 17-163])
- Fix implementation status check: accept 'write_bitstream' status as success
(Vivado auto-proceeds to write_bitstream, making status != '*Complete*')
- Wrap bitstream launch_runs in catch{} to handle already-running case
Fixes applied to: build17, build18, build19, build20, build21
CDC fixes across 6 RTL files based on post-implementation report_cdc analysis:
- P0: sync stm32_mixers_enable and new_chirp_pulse to clk_120m via toggle CDC
in radar_transmitter, add ft601 reset synchronizer and USB holding
registers with proper edge detection in usb_data_interface
- P1: add ASYNC_REG to edge_detector, convert new_chirp_frame to toggle CDC,
fix USB valid edge detect to use fully-synced signal
- P2: register Gray encoding in cdc_adc_to_processing source domain, sync
ft601_txe and stm32_mixers_enable for status_reg in radar_system_top
- Safety: add in_bin_count overflow guard in range_bin_decimator to prevent
downstream BRAM corruption
All 13 regression test suites pass (159 individual tests).
Jason