test(fpga): F-2.2 adversarial mid-frame reset sweep + F-0.1 TB plumbing

G9B adds a 4-iteration reset sweep on top of the existing e2e harness:
- Reset is injected at four offsets (3/7/12/18 us) into a steady-state
  auto-scan burst, with mixed short/long hold durations (20-120 clk_100m)
  to exercise asynchronous assert paths through the FSM + CDCs.
- Each iteration asserts: system_status drops to 0 during reset,
  new_chirp_frame resumes post-release, and obs_range_valid_count
  advances — proving the full DDC->MF chain recovers, not just the
  transmitter FSM.

The stub and three existing testbenches are updated to drive the new
adc_or_p/n ports tied to 1'b0/1'b1, matching the F-0.1 RTL change.

9_Firmware/9_2_FPGA/tb/ad9484_interface_400m_stub.v

@@ -19,6 +19,10 @@ module ad9484_interface_400m (
     input wire [7:0] adc_d_n,
     input wire adc_dco_p,
     input wire adc_dco_n,
+    // Audit F-0.1: AD9484 OR (overrange) LVDS pair — stub treats adc_or_p as
+    // the single-ended overrange flag, adc_or_n is ignored.
+    input wire adc_or_p,
+    input wire adc_or_n,
 
     // System Interface
     input wire sys_clk,
@@ -27,7 +31,8 @@ module ad9484_interface_400m (
     // Output at 400MHz domain
     output wire [7:0] adc_data_400m,
     output wire adc_data_valid_400m,
-    output wire adc_dco_bufg
+    output wire adc_dco_bufg,
+    output wire adc_overrange_400m
 );
 
 // Pass-through clock (no BUFG needed in simulation)
@@ -50,4 +55,15 @@ end
 assign adc_data_400m = adc_data_400m_reg;
 assign adc_data_valid_400m = adc_data_valid_400m_reg;
 
+// Audit F-0.1: 1-cycle pipeline of adc_or_p to match the real IDDR+register
+// capture path. TB drives adc_or_p directly with the overrange flag.
+reg adc_overrange_400m_reg;
+always @(posedge adc_dco_p or negedge reset_n) begin
+    if (!reset_n)
+        adc_overrange_400m_reg <= 1'b0;
+    else
+        adc_overrange_400m_reg <= adc_or_p;
+end
+assign adc_overrange_400m = adc_overrange_400m_reg;
+
 endmodule

9_Firmware/9_2_FPGA/tb/radar_system_tb.v

@@ -487,6 +487,8 @@ radar_system_top #(
     .adc_d_n(adc_d_n),
     .adc_dco_p(adc_dco_p),
     .adc_dco_n(adc_dco_n),
+    .adc_or_p(1'b0),
+    .adc_or_n(1'b1),
     .adc_pwdn(adc_pwdn),
     
     // STM32 Control

9_Firmware/9_2_FPGA/tb/tb_radar_receiver_final.v

@@ -139,6 +139,8 @@ radar_receiver_final dut (
     // ADC "LVDS" -- stub treats adc_d_p as single-ended data
     .adc_d_p(adc_data),
     .adc_d_n(~adc_data),       // Complement (ignored by stub)
+    .adc_or_p(1'b0),           // F-0.1: no overrange stimulus in this TB
+    .adc_or_n(1'b1),
     .adc_dco_p(clk_400m),      // 400 MHz clock
     .adc_dco_n(~clk_400m),     // Complement (ignored by stub)
     .adc_pwdn(),

9_Firmware/9_2_FPGA/tb/tb_system_e2e.v

@@ -427,6 +427,8 @@ radar_system_top #(
     .adc_d_n(adc_d_n),
     .adc_dco_p(adc_dco_p),
     .adc_dco_n(adc_dco_n),
+    .adc_or_p(1'b0),
+    .adc_or_n(1'b1),
     .adc_pwdn(adc_pwdn),
 
     .stm32_new_chirp(stm32_new_chirp),
@@ -938,6 +940,106 @@ initial begin
 
     $display("");
 
+    // ================================================================
+    // GROUP 9B: Adversarial reset sweep (audit F-2.2)
+    // ================================================================
+    // Drive the same auto-scan pipeline, then inject reset at four distinct
+    // offsets relative to a known-good start of operation. For each offset
+    // the system must:
+    //   (a) present system_status == 0 while held in reset
+    //   (b) produce at least one additional new_chirp_frame within the
+    //       observation window after reset release
+    //   (c) advance obs_range_valid_count (confirms full DDC+MF chain resumes)
+    // The four offsets are chosen to hit mid-chirp, mid-listen, and around
+    // the short/long chirp boundary, which covers the interesting FSM and
+    // CDC transitions in the pipeline.
+    $display("--- Group 9B: Adversarial reset sweep (F-2.2) ---");
+    begin : reset_sweep
+        integer sweep_i;
+        integer sweep_baseline_range;
+        integer sweep_baseline_chirp;
+        integer sweep_offsets [0:3];
+        integer sweep_holds   [0:3];
+        reg     sweep_ok;
+
+        // Reset injection offsets (ns) after the last auto-scan reconfigure.
+        // 3 us / 7 us / 12 us / 18 us — sprayed across a short-chirp burst.
+        sweep_offsets[0] = 3000;
+        sweep_offsets[1] = 7000;
+        sweep_offsets[2] = 12000;
+        sweep_offsets[3] = 18000;
+        // Reset-assert durations mix short (~20 clk_100m) and long (~120)
+        sweep_holds[0] = 200;
+        sweep_holds[1] = 1200;
+        sweep_holds[2] = 400;
+        sweep_holds[3] = 800;
+
+        for (sweep_i = 0; sweep_i < 4; sweep_i = sweep_i + 1) begin
+            // Re-seed auto-scan from a clean base each iteration
+            reset_n = 0;
+            bfm_rx_wr_ptr = 0;
+            bfm_rx_rd_ptr = 0;
+            #200;
+            reset_n = 1;
+            #500;
+            stm32_mixers_enable = 1;
+            ft601_txe = 0;
+            bfm_send_cmd(8'h04, 8'h00, 16'h0001);
+            #500;
+            bfm_send_cmd(8'h01, 8'h00, 16'h0001);
+            bfm_send_cmd(8'h10, 8'h00, 16'd100);
+            bfm_send_cmd(8'h11, 8'h00, 16'd200);
+            bfm_send_cmd(8'h12, 8'h00, 16'd100);
+            bfm_send_cmd(8'h13, 8'h00, 16'd20);
+            bfm_send_cmd(8'h14, 8'h00, 16'd100);
+            bfm_send_cmd(8'h15, 8'h00, 16'd4);
+
+            // Let the pipeline reach steady-state and capture a baseline
+            #30000;
+            sweep_baseline_range = obs_range_valid_count;
+            sweep_baseline_chirp = obs_chirp_frame_count;
+
+            // Wait out the configured offset, then assert reset asynchronously
+            #(sweep_offsets[sweep_i]);
+            reset_n = 0;
+            #(sweep_holds[sweep_i]);
+            sweep_ok = (system_status == 4'b0000);
+            check(sweep_ok,
+                  "G9B.a: system_status drops to 0 during injected reset");
+
+            // Release reset, re-configure (regs are cleared), allow recovery
+            reset_n = 1;
+            #500;
+            stm32_mixers_enable = 1;
+            ft601_txe = 0;
+            bfm_send_cmd(8'h04, 8'h00, 16'h0001);
+            #500;
+            bfm_send_cmd(8'h01, 8'h00, 16'h0001);
+            bfm_send_cmd(8'h10, 8'h00, 16'd100);
+            bfm_send_cmd(8'h11, 8'h00, 16'd200);
+            bfm_send_cmd(8'h12, 8'h00, 16'd100);
+            bfm_send_cmd(8'h13, 8'h00, 16'd20);
+            bfm_send_cmd(8'h14, 8'h00, 16'd100);
+            bfm_send_cmd(8'h15, 8'h00, 16'd4);
+
+            sweep_baseline_range = obs_range_valid_count;
+            sweep_baseline_chirp = obs_chirp_frame_count;
+            #60000;   // 60 us — two+ short-chirp frames
+
+            check(obs_chirp_frame_count > sweep_baseline_chirp,
+                  "G9B.b: new_chirp_frame resumes after injected reset");
+            check(obs_range_valid_count > sweep_baseline_range,
+                  "G9B.c: range pipeline resumes after injected reset");
+
+            $display("  [F-2.2] iter=%0d offset=%0dns hold=%0dns chirps=+%0d ranges=+%0d",
+                     sweep_i, sweep_offsets[sweep_i], sweep_holds[sweep_i],
+                     obs_chirp_frame_count - sweep_baseline_chirp,
+                     obs_range_valid_count - sweep_baseline_range);
+        end
+    end
+
+    $display("");
+
     // ================================================================
     // GROUP 10: STREAM CONTROL (Gap 2)
     // ================================================================