TactilityProject · KenVanHoeylandt · Jun 19, 2026 · Jun 19, 2026 · Jun 19, 2026 · Jun 19, 2026
diff --git a/Apps/M5UnitTest/main/Source/GroveLookup.cpp b/Apps/M5UnitTest/main/Source/GroveLookup.cpp
@@ -0,0 +1,45 @@
+#include "GroveLookup.h"
+#include <tactility/drivers/i2c_controller.h>
+#include <tactility/drivers/uart_controller.h>
+
+namespace {
+
+struct GroveChildSearch {
+    const DeviceType* childType;
+    Device* result;
+};
+
+bool onGroveDevice(Device* groveDevice, void* context) {
+    auto* search = static_cast<GroveChildSearch*>(context);
+
+    GroveMode mode;
+    if (grove_get_mode(groveDevice, &mode) != ERROR_NONE) return true;
+    if (mode != (search->childType == &I2C_CONTROLLER_TYPE ? GROVE_MODE_I2C : GROVE_MODE_UART)) return true;
+
+    device_for_each_child(groveDevice, search, [](Device* child, void* ctx) -> bool {
+        auto* s = static_cast<GroveChildSearch*>(ctx);
+        if (device_get_type(child) == s->childType && device_is_ready(child)) {
+            s->result = child;
+            return false; // stop - found it
+        }
+        return true;
+    });
+
+    return search->result == nullptr; // stop outer iteration once found
+}
+
+Device* findGroveChild(const DeviceType* childType) {
+    GroveChildSearch search{childType, nullptr};
+    device_for_each_of_type(&GROVE_TYPE, &search, onGroveDevice);
+    return search.result;
+}
+
+} // namespace
+
+Device* findGroveI2cDevice() {
+    return findGroveChild(&I2C_CONTROLLER_TYPE);
+}
+
+Device* findGroveUartDevice() {
+    return findGroveChild(&UART_CONTROLLER_TYPE);
+}
diff --git a/Apps/M5UnitTest/main/Source/GroveLookup.h b/Apps/M5UnitTest/main/Source/GroveLookup.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <tactility/device.h>
+#include <tactility/drivers/grove.h>
+
+// Finds the I2C controller device exposed by the first grove port currently
+// in GROVE_MODE_I2C, by checking each grove port's child device type
+// (not by name - grove port names are not guaranteed, e.g. "port_a").
+Device* findGroveI2cDevice();
+
+// Same as findGroveI2cDevice() but for UART mode.
+Device* findGroveUartDevice();
diff --git a/Apps/M5UnitTest/main/Source/TestUnit8Encoder.cpp b/Apps/M5UnitTest/main/Source/TestUnit8Encoder.cpp
@@ -1,4 +1,5 @@
 #include "TestUnit8Encoder.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -93,9 +94,9 @@ void TestUnit8Encoder::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* a
     lv_obj_set_flex_grow(lblSwitch_, 1);
     dotSwitch_ = makeDot(swCard);
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
-        lv_label_set_text(lblStatus_, "i2c1 not found");
+        lv_label_set_text(lblStatus_, "grove0_i2c not found");
         return;
     }
 

diff --git a/Apps/M5UnitTest/main/Source/TestUnitByteButton.cpp b/Apps/M5UnitTest/main/Source/TestUnitByteButton.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitByteButton.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -56,10 +57,10 @@ void TestUnitByteButton::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest*
     lv_obj_set_style_text_font(hint, lvgl_get_text_font(FONT_SIZE_SMALL), 0);
     lv_label_set_text(hint, "Press buttons - LEDs toggle");
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
         for (int i = 0; i < BTN_COUNT; i++) lv_obj_set_style_bg_color(indicators_[i], lv_color_hex(COLOR_ERROR), 0);
-        lv_label_set_text(hint, "i2c1 not found");
+        lv_label_set_text(hint, "grove0_i2c not found");
         return;
     }
 

diff --git a/Apps/M5UnitTest/main/Source/TestUnitCardKB2.cpp b/Apps/M5UnitTest/main/Source/TestUnitCardKB2.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitCardKB2.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/drivers/uart_controller.h>
@@ -116,10 +117,10 @@ void TestUnitCardKB2::connectI2C() {
     lv_obj_delete(connectOverlay_);
     connectOverlay_ = nullptr;
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
         buildMainUI();
-        lv_label_set_text(lblHistory_, "i2c1 not found");
+        lv_label_set_text(lblHistory_, "grove0_i2c not found");
         return;
     }
 
@@ -145,10 +146,10 @@ void TestUnitCardKB2::connectUart() {
     lv_obj_delete(connectOverlay_);
     connectOverlay_ = nullptr;
 
-    Device* uart = device_find_by_name("uart1");
+    Device* uart = findGroveUartDevice();
     buildMainUI();
     if (!uart) {
-        lv_label_set_text(lblHistory_, "uart1 not found");
+        lv_label_set_text(lblHistory_, "grove0_uart not found");
         return;
     }
     if (!unit_.beginUart(uart)) {

diff --git a/Apps/M5UnitTest/main/Source/TestUnitJoystick2.cpp b/Apps/M5UnitTest/main/Source/TestUnitJoystick2.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitJoystick2.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -56,9 +57,9 @@ void TestUnitJoystick2::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest*
     lv_obj_set_style_border_width(dot_, 0, 0);
     lv_obj_set_pos(dot_, (JOY_AREA - DOT_SIZE) / 2, (JOY_AREA - DOT_SIZE) / 2);
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
-        lv_label_set_text(lblXY_, "i2c1 not found");
+        lv_label_set_text(lblXY_, "grove0_i2c not found");
         return;
     }
 

diff --git a/Apps/M5UnitTest/main/Source/TestUnitLcd.cpp b/Apps/M5UnitTest/main/Source/TestUnitLcd.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitLcd.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -87,9 +88,9 @@ void TestUnitLcd::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app) {
     lv_label_set_text(lText, "Write Text");
     lv_obj_set_style_text_font(lText, fnt, 0);
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
-        lv_label_set_text(lblStatus_, "i2c1 not found");
+        lv_label_set_text(lblStatus_, "grove0_i2c not found");
         return;
     }
 

diff --git a/Apps/M5UnitTest/main/Source/TestUnitLcdGfx.cpp b/Apps/M5UnitTest/main/Source/TestUnitLcdGfx.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitLcdGfx.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -65,8 +66,8 @@ void TestUnitLcdGfx::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app
     lv_obj_set_width(lblLog_, LV_PCT(100));
     lv_label_set_text(lblLog_, "");
 
-    Device* i2c = device_find_by_name("i2c1");
-    if (!i2c) { lv_label_set_text(lblPhase_, "i2c1 not found"); return; }
+    Device* i2c = findGroveI2cDevice();
+    if (!i2c) { lv_label_set_text(lblPhase_, "grove0_i2c not found"); return; }
 
     if (lcd_.begin(i2c)) {
         usingPaHub_ = false;

diff --git a/Apps/M5UnitTest/main/Source/TestUnitMidi.cpp b/Apps/M5UnitTest/main/Source/TestUnitMidi.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitMidi.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -84,7 +85,7 @@ void TestUnitMidi::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app)
     lv_obj_t* lOff = lv_label_create(btnOff); lv_label_set_text(lOff, "Note Off");
     lv_obj_set_style_text_font(lOff, fntS, 0);
 
-    Device* uart = device_find_by_name(UART_DEVICE);
+    Device* uart = findGroveUartDevice();
     if (!uart || !device_is_ready(uart) || !unit_.begin(uart)) {
         lv_label_set_text(lblStatus_, "MIDI UART not available");
         updateLabels();

diff --git a/Apps/M5UnitTest/main/Source/TestUnitMidi.h b/Apps/M5UnitTest/main/Source/TestUnitMidi.h
@@ -17,9 +17,6 @@ class TestUnitMidi final : public TestViewBase {
     uint8_t   note_       = 60;  // middle C
     bool      notePlaying_= false;
 
-    // UART device name for MIDI unit (adjust to match your board wiring)
-    static constexpr const char* UART_DEVICE = "uart1";
-
     static void onNoteOnClicked(lv_event_t* e);
     static void onNoteOffClicked(lv_event_t* e);
     static void onChUp(lv_event_t* e);

diff --git a/Apps/M5UnitTest/main/Source/TestUnitPaHub.cpp b/Apps/M5UnitTest/main/Source/TestUnitPaHub.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitPaHub.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/drivers/i2c_controller.h>
@@ -60,7 +61,7 @@ void TestUnitPaHub::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app)
         lv_label_set_text_fmt(lblCh_[i], "CH%d: -", i);
     }
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c || !hub_.begin(i2c)) {
         lv_label_set_text(lblStatus_, "PaHub not found");
         return;
@@ -95,16 +96,16 @@ void TestUnitPaHub::probeSelected() {
 
     hub_.select((uint8_t)selChannel_);
 
-    // Scan I2C addresses 0x08-0x77 on this channel
-    Device* i2c = device_find_by_name("i2c1");
+    // Probe known unit addresses only (full-range scan can wedge the ESP-IDF i2c_master bus FSM)
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
-        lv_label_set_text_fmt(lblCh_[selChannel_], "CH%d: i2c1 not found", selChannel_);
+        lv_label_set_text_fmt(lblCh_[selChannel_], "CH%d: grove0_i2c not found", selChannel_);
         hub_.deselect();
         return;
     }
     char found[256] = "Found: ";
     bool any = false;
-    for (uint8_t addr = 0x08; addr < 0x78; addr++) {
+    for (uint8_t addr : KNOWN_UNIT_ADDRS) {
         if (i2c_controller_has_device_at_address(i2c, addr,
             pdMS_TO_TICKS(10)) == ERROR_NONE) {
             size_t remaining = sizeof(found) - strlen(found) - 1;

diff --git a/Apps/M5UnitTest/main/Source/TestUnitRfid2.cpp b/Apps/M5UnitTest/main/Source/TestUnitRfid2.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitRfid2.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -101,7 +102,7 @@ void TestUnitRfid2::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app)
     lv_label_set_text(btnLbl, "Clear");
 
     // ── Device discovery ─────────────────────────────────────────────────────
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) return;
 
     if (unit_.begin(i2c)) {

diff --git a/Apps/M5UnitTest/main/Source/TestUnitScroll.cpp b/Apps/M5UnitTest/main/Source/TestUnitScroll.cpp
@@ -1,4 +1,5 @@
 #include "TestUnitScroll.h"
+#include "GroveLookup.h"
 #include "UiScale.h"
 #include <tactility/device.h>
 #include <tactility/lvgl_fonts.h>
@@ -57,9 +58,9 @@ void TestUnitScroll::onStart(lv_obj_t* parent, AppHandle handle, M5UnitTest* app
     sliderB_ = makeSlider("B");
     lv_label_set_text(lblLed_, "LED: #000000");
 
-    Device* i2c = device_find_by_name("i2c1");
+    Device* i2c = findGroveI2cDevice();
     if (!i2c) {
-        lv_label_set_text(lblCounter_, "i2c1 not found");
+        lv_label_set_text(lblCounter_, "grove0_i2c not found");
         return;
     }
 

diff --git a/Libraries/M5UnitModules/Include/UnitCommon.h b/Libraries/M5UnitModules/Include/UnitCommon.h
@@ -21,6 +21,20 @@ static constexpr uint32_t UNIT_I2C_PROBE_TIMEOUT_MS = 10;  // shorter timeout fo
 static constexpr uint32_t UNIT_STM32_READ_DELAY_MS  =  2;  // STM32 needs STOP + delay before read
 static constexpr uint16_t UNIT_MAX_WRITE_PAYLOAD     = 32;  // max bytes in a single I2C write
 
+// I2C addresses of the unit modules this library can drive (excludes PaHub itself
+// and UART-only units like MIDI). Used by PaHub channel probing instead of a full
+// 0x08-0x77 bus scan: the ESP-IDF i2c_master driver's probe op can wedge the bus
+// FSM after heavy NACK traffic, so scanning only known addresses avoids that.
+static constexpr uint8_t KNOWN_UNIT_ADDRS[] = {
+    0x28, // UnitRfid2
+    0x3E, // UnitLcd
+    0x40, // UnitScroll
+    0x41, // Unit8Encoder
+    0x47, // UnitByteButton
+    0x5F, // UnitCardKB2
+    0x63, // UnitJoystick2
+};
+
 // Probe whether a device exists at the given address on the given I2C bus.
 inline bool unitProbe(Device* dev, uint8_t addr) {
     return i2c_controller_has_device_at_address(