feat(firmware): on-device Joystick Dual/Single settings menu

Add glue/settings_view.hpp: wire_settings(mode) registers a "Joystick"
SingleSelectView on the MEMLNaut display carousel (TFT + rotary encoder, same
DisplayDriver as SystemView/SelfTest). For the 4-input two-joystick modes,
"Single" pins ML input channels 2,3 (the second joystick) to neutral via
ModeBase::set_input_pinned — the network is never rebuilt and trained state
survives toggling. Default is Dual. Only registered when input arity == 4.

Called from MEMLNaut-NISPS.ino setup() after addSystemInfoView(). MAP.md +
CLAUDE.md glue listings updated.

NOTE: compile-unverified — no arduino-cli/RP2350 toolchain on this host and no
hardware; needs scripts/build-firmware.sh + a flash test (chokepoint A).

CLAUDE.md

@@ -58,7 +58,8 @@ firmware/MEMLNaut-NISPS/
 │   ├── midi_io.hpp        # MIDI in → mode handlers; drain ControlEvent ring → MIDI UART
 │   ├── mode_select.hpp    # type aliases firmware mode name → nisps::modes::*Mode
 │   ├── input_router.hpp   # wire_inputs() entry point
-│   └── output_router.hpp  # drain_outputs() entry point
+│   ├── output_router.hpp  # drain_outputs() entry point
+│   └── settings_view.hpp  # wire_settings(): TFT/rotary menu (Joystick Dual/Single for 4-in modes)
 └── src/{memllib,daisysp,nisps}    # symlinks (Arduino-CLI sketch tree convention)
 ```
 

MAP.md

@@ -23,6 +23,7 @@ MEMLNaut-NISPS — Neural Interactive Shaping of Parameter Spaces. One C++20 cod
   - `mode_select.hpp` — type aliases mapping firmware mode identifiers to `nisps::modes::*Mode` C++ types. Build script rewrites the active line. Includes the six `MEMLNautModeExtSynth*` external-synth variants (one per device template in `nisps/midi`, e.g. `MEMLNautModeExtSynthSub37`). Also defines the `MEMLNautModeSelfTest` pseudo-variant (tag type) + the `NISPS_ST_*`/`NISPS_ST_CAT` token-paste macros the `.ino` uses to compute `NISPS_SELFTEST`. Note: `src/nisps/` exposes each referenced top-level nisps subdir as a symlink — `midi` was added alongside `core/dsp/engines/ml/modes`.
   - `selftest.hpp` — standalone guided hardware self-test rig (`SelfTest` variant; no engine/ML). Step-driven state machine on a `SelfTestView`: TFT prompts the operator through every control, auto-advances on detection, encoder-press skips. Ends with optional L/R/BOTH sine-sweep headphone check (core 1 block callback) + MIDI loopback-cable test. Lives firmware-side (touches TFT + raw pins) so it stays out of platform-agnostic `nisps/`.
   - `input_router.hpp`, `output_router.hpp` — top-level `wire_inputs()` / `drain_outputs()` entry points.
+  - `settings_view.hpp` — `wire_settings(mode)`: adds on-device settings views to the MEMLNaut display carousel (TFT + rotary encoder). Joystick Dual/Single toggle for the 4-input ("two 2-D joystick") modes — "Single" pins ML input channels 2,3 to neutral via `ModeBase::set_input_pinned` (no net rebuild). Registered in the `.ino` after `addSystemInfoView()`.
 - `firmware/MEMLNaut-NISPS/src/{memllib,daisysp,nisps}` — symlinks (Arduino-CLI requires sketch-tree includes; preprocessor refuses `..` in headers).
 - `firmware/README.md` — structure + build instructions.
 

firmware/MEMLNaut-NISPS/MEMLNaut-NISPS.ino

@@ -31,6 +31,7 @@
 #include "glue/midi_io.hpp"
 #include "glue/mode_select.hpp"
 #include "glue/output_router.hpp"
+#include "glue/settings_view.hpp"
 
 // ---- Mode selection ----
 // Build script rewrites which line is uncommented.
@@ -141,6 +142,8 @@ void setup() {
     }
 
     MEMLNaut::Instance()->addSystemInfoView();
+    // Settings menu (e.g. Joystick: Dual/Single for the 4-input modes).
+    nisps_firmware::wire_settings(g_mode);
     Serial.println("Finished initialising core 0.");
 }
 

firmware/MEMLNaut-NISPS/glue/settings_view.hpp

@@ -0,0 +1,64 @@
+// glue/settings_view.hpp — on-device settings menu views (TFT + rotary encoder).
+//
+// Adds entries to the MEMLNaut display carousel (the same DisplayDriver the
+// SystemView and SelfTest use). Navigation: rotate to move between views;
+// press to focus a view; rotate-while-focused to change its value; press
+// again to unfocus. See src/memllib/.../display/DisplayDriver.hpp.
+//
+// Currently provides:
+//   * Joystick: Dual / Single — for the 4-input ("two 2-D joystick") modes,
+//     toggles whether the SECOND joystick (input channels 2,3) feeds the ML
+//     engine. "Single" pins those channels to the neutral value (0.5) via the
+//     platform-agnostic ModeBase pin mechanism, so the network is never
+//     rebuilt and trained state survives toggling. Default is Dual (the 4-D
+//     variant naturally uses both joysticks).
+//
+// Only registered for modes whose input arity is exactly 4 (the two-joystick
+// modes); other modes (e.g. SoundAnalysisMIDI, whose joystick channels are not
+// 2,3) get no joystick toggle.
+
+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <memory>
+#include <span>
+
+#include "../src/memllib/hardware/memlnaut/MEMLNaut.hpp"
+#include "../src/memllib/hardware/memlnaut/display/SingleSelectView.hpp"
+
+namespace nisps_firmware {
+
+// The second 2-D joystick maps to ML input channels 2 and 3 (joy_z / joy_w).
+inline constexpr std::size_t kSecondJoystickCh0 = 2u;
+inline constexpr std::size_t kSecondJoystickCh1 = 3u;
+
+// Add the settings views for `mode` to the display carousel. Must run AFTER
+// MEMLNaut::Initialize() (so the display + TFT exist) and after
+// addSystemInfoView(), on core 0.
+template <typename ModeT>
+inline void wire_settings(ModeT& mode) {
+    if constexpr (ModeT::input_channel_count() == 4u) {
+        MEMLNaut* meml = MEMLNaut::Instance();
+        if (!meml || !meml->disp) return;
+
+        // Kept alive for the program lifetime (the carousel holds a shared_ptr
+        // too, but this guarantees ownership regardless of view churn).
+        static std::shared_ptr<SingleSelectView> joystick_view;
+        joystick_view = std::make_shared<SingleSelectView>("Joystick");
+        meml->disp->AddView(joystick_view);  // calls Setup() → creates the selector
+
+        // Index 0 = Dual (default, no pinning); index 1 = Single.
+        std::array<String, 2u> options = { String("Dual"), String("Single") };
+        joystick_view->setOptions(std::span<String>(options.data(), options.size()));
+        joystick_view->setNewVoiceCallback([&mode](std::size_t idx) {
+            const bool single = (idx == 1u);
+            mode.set_input_pinned(kSecondJoystickCh0, single);
+            mode.set_input_pinned(kSecondJoystickCh1, single);
+        });
+    } else {
+        (void)mode;
+    }
+}
+
+}  // namespace nisps_firmware