control register instead of reset output

cores/signal/signal_scope/rtl/signal_scope_q15.v

@@ -17,11 +17,14 @@ module signal_scope_q15 #(
 );
     localparam aw = `CLOG2(depth);
     localparam [aw-1:0] depth_last = depth-1;
+    localparam [31:0] reg_base_addr = 32'h8000_0000;
+    localparam [3:0] reg_control = 4'h0;
+    localparam [3:0] reg_status = 4'h1;
 
     (* ram_style = "block" *) reg [16*4-1:0] mem[depth-1:0];
     reg [aw-1:0] counter;
     reg count_enable;
-    reg rearm_prev;
+    reg arm_req;
 
     reg [15:0] signal_a;
     reg [15:0] signal_b;
@@ -40,8 +43,9 @@ module signal_scope_q15 #(
     wire wb_stb;
     reg [31:0] wb_rdt;
     reg wb_ack;
-    wire rearm_cmd;
     wire [aw-1:0] wb_mem_idx = wb_adr[aw+2:3];
+    wire wb_is_reg = (wb_adr[31:28] == reg_base_addr[31:28]);
+    wire [3:0] wb_reg_idx = wb_adr[5:2];
 
     jtag_wb_bridge #(
         .chain(chain),
@@ -57,14 +61,14 @@ module signal_scope_q15 #(
         .o_wb_stb(wb_stb),
         .i_wb_rdt(wb_rdt),
         .i_wb_ack(wb_ack),
-        .o_cmd_reset(rearm_cmd)
+        .o_cmd_reset()
     );
 
     always @(posedge i_clk) begin
         if(i_rst) begin
             counter <= {aw{1'b0}};
             count_enable <= 1'b0;
-            rearm_prev <= 1'b0;
+            arm_req <= 1'b0;
             wb_ack <= 1'b0;
             wb_rdt <= 32'b0;
             signal_a <= 0;
@@ -95,9 +99,8 @@ module signal_scope_q15 #(
                 signal_d_pending <= 1'b1;
             end
 
-            // Rearm on rising edge of reset command from JTAG bridge.
-            rearm_prev <= rearm_cmd;
-            if(rearm_cmd && !rearm_prev) begin
+            // Arm/rearm capture on control-register command pulse.
+            if(arm_req) begin
                 counter <= {aw{1'b0}};
                 count_enable <= 1'b1;
                 signal_a_pending <= 1'b0;
@@ -110,7 +113,7 @@ module signal_scope_q15 #(
             if(count_enable && signal_a_pending && signal_b_pending && signal_c_pending && signal_d_pending) begin
                 if(counter <= depth_last) begin
                     mem[counter] <= {signal_a, signal_b, signal_c, signal_d};
-                    counter <= counter + 3'd1;
+                    counter <= counter + {{(aw-1){1'b0}}, 1'b1};
                     if(counter == depth_last)
                         count_enable <= 1'b0;
                 end else begin
@@ -122,16 +125,40 @@ module signal_scope_q15 #(
                 signal_d_pending <= 1'b0;
             end
 
-            // Simple WB slave response for JTAG reads (32-bit = 2x16-bit samples).
+            // WB slave response: register window + capture memory window.
+            arm_req <= 1'b0;
             wb_ack <= wb_cyc & wb_stb & !wb_ack;
             if(wb_cyc & wb_stb & !wb_ack) begin
                 if(wb_we) begin
                     wb_rdt <= 32'b0;
-                end else if(wb_mem_idx <= depth_last) begin
-                    // A single frame is 64-bit: {a, b, c, d}. WB reads low/high 32-bit halves.
-                    wb_rdt <= wb_adr[2] ? mem[wb_mem_idx][63:32] : mem[wb_mem_idx][31:0];
+                    if(wb_is_reg) begin
+                        // Keep register write decode in one case so new writable registers
+                        // can be added without touching memory-path logic.
+                        case(wb_reg_idx)
+                            reg_control: begin
+                                // Bit 0: write-1 to arm/rearm scope (pulse).
+                                if(wb_sel[0] && wb_dat[0])
+                                    arm_req <= 1'b1;
+                            end
+                            default: begin
+                            end
+                        endcase
+                    end
                 end else begin
-                    wb_rdt <= 32'b0;
+                    if(wb_is_reg) begin
+                        case(wb_reg_idx)
+                            // Write-pulse register: reads as zero.
+                            reg_control: wb_rdt <= 32'b0;
+                            // Basic status for polling/debug.
+                            reg_status: wb_rdt <= {30'b0, count_enable, (counter == depth_last)};
+                            default: wb_rdt <= 32'b0;
+                        endcase
+                    end else if(wb_mem_idx <= depth_last) begin
+                        // A single frame is 64-bit: {a, b, c, d}. WB reads low/high 32-bit halves.
+                        wb_rdt <= wb_adr[2] ? mem[wb_mem_idx][63:32] : mem[wb_mem_idx][31:0];
+                    end else begin
+                        wb_rdt <= 32'b0;
+                    end
                 end
             end
 

cores/signal/signal_scope/tool/capture_plot.py

@@ -6,6 +6,11 @@ from pathlib import Path
 
 import matplotlib.pyplot as plt
 
+MEM_BASE = 0x00000000
+REG_BASE = 0x80000000
+REG_CONTROL = REG_BASE + 0x00
+REG_STATUS = REG_BASE + 0x04
+
 
 def _add_bridge_module_path() -> None:
     here = Path(__file__).resolve()
@@ -64,16 +69,15 @@ def parse_args() -> argparse.Namespace:
 def capture_once(bridge, args: argparse.Namespace) -> list[tuple[int, int, int, int]]:
     samples = []
     frame_count = args.depth
-    print("[signal_scope] Arming scope (set_reset=1 -> 0)...")
-    bridge.set_reset(True)
-    bridge.set_reset(False)
+    print("[signal_scope] Arming scope (write REG_CONTROL bit0=1)...")
+    bridge.write32(REG_CONTROL, 0x1)
     if args.wait_s > 0:
         print(f"[signal_scope] Waiting {args.wait_s:.3f}s for capture to complete...")
         time.sleep(args.wait_s)
 
     print(f"[signal_scope] Reading back {frame_count} frames...")
     for idx in range(frame_count):
-        base = idx * 8
+        base = MEM_BASE + idx * 8
         low = bridge.read32(base)
         high = bridge.read32(base + 4)
 
@@ -151,6 +155,8 @@ def main() -> int:
         bridge.clear_flags()
         bridge.ping()
         print("[signal_scope] Bridge ready")
+        status = bridge.read32(REG_STATUS)
+        print(f"[signal_scope] Status: 0x{status:08x}")
 
         fig, ax = plt.subplots(figsize=(12, 4))
         capture_idx = 1