bluenevus · Oct 6, 2026 · Oct 6, 2026
diff --git a/AI_RULES.md b/AI_RULES.md
@@ -119,9 +119,11 @@ menu of short prompts; the screen is edge-to-edge text (no borders or decoration
   touch, detected by the `espressif/m5stack_tab5` BSP), rotated to 1280x720 landscape by the
   PPA (`LV_DISPLAY_ROTATION_90`, keyboard at the bottom); LVGL buffers in PSRAM. Backlight
   GPIO 22. System I2C on GPIO 31/32 (BSP): IO expanders, touch, codecs, INA226 battery monitor.
-- IO expanders (PI4IOE5V6408), reset by the BSP at init: 0x43 P1 speaker amp, P2 5 V to the
-  side port (the keyboard needs it), P4 LCD reset, P5 touch reset; 0x44 P0 ESP32-C6 power,
-  P5 fast-charge (low = on), P7 charger enable. `board::init_power()` sets them: the battery
+- IO expanders (PI4IOE5V6408), reset by the BSP at init: 0x43 P0 antenna (low = internal),
+  P1 speaker amp, P2 5 V to the side port (the keyboard needs it), P4 LCD reset, P5 touch
+  reset; 0x44 P0 ESP32-C6 power, P3 USB-A 5 V, P4 power-off pulse, P5 quick charge (low = on),
+  P7 charger enable. The reset leaves every pin high-impedance: an output only drives once set
+  push-pull (`esp_io_expander_set_output_mode()`). `board::init_power()` sets them: the battery
   charges only while firmware enables the charger.
 - Keyboard: STM32 at I2C 0x6D on its own bus (G0 SDA, G1 SCL), INT G50 low while events are
   queued, raw mode (press/release by row/column; reading 0x20 pops an event, so never retry

diff --git a/README.md b/README.md
@@ -96,7 +96,7 @@ OpenAI, and only while you use ChatGPT.
   the Tab5 keyboard just press them: Ctrl+letter, Tab and Esc go straight to the server.
 - **History**: roll the trackball left (older) or right (newer). Tab5: Up / Down.
 - **Disconnect**: type `exit` to return to the menu.
-- **ChatGPT**: type to chat, or hold the trackball (Tab5: hold Ctrl+Space) to speak and let
+- **ChatGPT**: type to chat, or hold the trackball (Tab5: hold Ctrl) to speak and let
   go to send. Start talking
   once `* Recording` shows. Your speech is transcribed by OpenAI's speech-to-text model, then
   sent as your message to the chat model you picked. If the microphone picks up nothing, the
@@ -118,7 +118,7 @@ at a time. Use one-shot commands instead, for example `top -n 1`.
 | Aa | Hold for capitals; tap for one capital; tap twice for caps lock |
 | Sym + key | The key's second symbol (`?` `/` `<` `>` `{` `}` `\|` `~` `:` `"` `=` `,`) |
 | Ctrl + letter | Control code to the server (Ctrl+C, Ctrl+D, Ctrl+Z, Ctrl+L ...) |
-| Ctrl+Space (hold) | Talk to ChatGPT; held for a second elsewhere, deletes the shown history entry |
+| Ctrl (hold on its own) | Talk to ChatGPT while held; held for a second elsewhere, deletes the shown history entry |
 
 Held keys repeat. The keyboard can be attached or removed while SimplrSSH runs, and the Tab5
 charges its battery over USB-C while SimplrSSH runs.

diff --git a/main/board_tab5.cpp b/main/board_tab5.cpp
@@ -21,16 +21,19 @@
 static const char *TAG = "board";
 
 const char* const board::NAME = "Tab5";
-const char* const board::HINT_TALK = "hold Ctrl+Space";
+const char* const board::HINT_TALK = "hold Ctrl";
 const char* const board::HINT_SCROLL = "Sym+Up/Down or drag: scroll.";
 const char* const board::HINT_HISTORY = "Up/Down: history.";
 const char* const board::SCREEN_DESC = "a 5-inch tablet with a 1280x720 text screen";
 
 // IO expander pins (M5Stack Tab5 pin map)
+static const uint32_t IO_RF_EXTERNAL = IO_EXPANDER_PIN_NUM_0;  // 0x43 P0: antenna, low = internal
 static const uint32_t IO_SPEAKER_EN = IO_EXPANDER_PIN_NUM_1;   // 0x43 P1: NS4150B amplifier
 static const uint32_t IO_EXT5V_EN = IO_EXPANDER_PIN_NUM_2;     // 0x43 P2: 5 V to the side port (keyboard)
 static const uint32_t IO1_WLAN_PWR_EN = IO_EXPANDER_PIN_NUM_0; // 0x44 P0: ESP32-C6 power
-static const uint32_t IO1_QC_DISABLE = IO_EXPANDER_PIN_NUM_5;  // 0x44 P5: low = fast charge allowed
+static const uint32_t IO1_USB5V_EN = IO_EXPANDER_PIN_NUM_3;    // 0x44 P3: 5 V out of the USB-A port
+static const uint32_t IO1_PWROFF = IO_EXPANDER_PIN_NUM_4;      // 0x44 P4: power-off pulse
+static const uint32_t IO1_NQC_EN = IO_EXPANDER_PIN_NUM_5;      // 0x44 P5: low = quick charge
 static const uint32_t IO1_CHARGE_EN = IO_EXPANDER_PIN_NUM_7;   // 0x44 P7: IP2326 charger on
 
 static bool s_wifi_ready = false;
@@ -50,23 +53,30 @@ const board::Ui& board::ui()
 
 void board::init_power()
 {
-    // Both expanders are reset by their driver on first use (all inputs): set what SimplrSSH needs
+    // Both expanders are reset by their driver on first use: set what SimplrSSH needs
     esp_io_expander_handle_t io = bsp_io_expander_init();
     esp_io_expander_handle_t io1 = bsp_io_expander1_init();
     if (!io || !io1) {
         ESP_LOGE(TAG, "IO expanders not reachable");
         return;
     }
-    // Speaker amplifier off until audio_tab5.cpp plays something; side-port 5 V on for the keyboard
-    esp_io_expander_set_dir(io, IO_SPEAKER_EN | IO_EXT5V_EN, IO_EXPANDER_OUTPUT);
-    esp_io_expander_set_level(io, IO_SPEAKER_EN, 0);
+    // The driver's reset leaves every pin high-impedance (pulled low): each output must be set
+    // push-pull, or it never drives. Levels as M5Stack's own firmware sets them.
+    // Internal antenna; speaker amplifier off until audio_tab5.cpp plays; side-port 5 V on for the keyboard
+    const uint32_t outs = IO_RF_EXTERNAL | IO_SPEAKER_EN | IO_EXT5V_EN;
+    esp_io_expander_set_dir(io, outs, IO_EXPANDER_OUTPUT);
+    esp_io_expander_set_level(io, IO_RF_EXTERNAL | IO_SPEAKER_EN, 0);
     esp_io_expander_set_level(io, IO_EXT5V_EN, 1);
+    esp_io_expander_set_output_mode(io, outs, IO_EXPANDER_OUTPUT_MODE_PUSH_PULL);
 
     // Power the WiFi co-processor now, so it has booted by the time WiFi is first used.
-    // The battery only charges while the firmware enables the charger (as the factory firmware does).
-    esp_io_expander_set_dir(io1, IO1_WLAN_PWR_EN | IO1_QC_DISABLE | IO1_CHARGE_EN, IO_EXPANDER_OUTPUT);
-    esp_io_expander_set_level(io1, IO1_WLAN_PWR_EN, 1);
-    esp_io_expander_set_level(io1, IO1_QC_DISABLE, 0);
+    // The battery only charges while the firmware enables the charger (standard charging, as
+    // the factory firmware does). USB-A 5 V off, no power-off pulse.
+    const uint32_t outs1 = IO1_WLAN_PWR_EN | IO1_USB5V_EN | IO1_PWROFF | IO1_NQC_EN | IO1_CHARGE_EN;
+    esp_io_expander_set_dir(io1, outs1, IO_EXPANDER_OUTPUT);
+    esp_io_expander_set_level(io1, IO1_USB5V_EN | IO1_PWROFF | IO1_CHARGE_EN, 0);
+    esp_io_expander_set_level(io1, IO1_WLAN_PWR_EN | IO1_NQC_EN, 1);
+    esp_io_expander_set_output_mode(io1, outs1, IO_EXPANDER_OUTPUT_MODE_PUSH_PULL);
     vTaskDelay(pdMS_TO_TICKS(50));
     esp_io_expander_set_level(io1, IO1_CHARGE_EN, 1);
 }

diff --git a/main/chat_app.cpp b/main/chat_app.cpp
@@ -1,7 +1,7 @@
 /*
  * ChatGPT App
  * One chat session with an OpenAI model: your messages right-aligned, replies
- * left-aligned, the input line at the bottom. Hold the trackball (Tab5: Ctrl+Space) to talk
+ * left-aligned, the input line at the bottom. Hold the trackball (Tab5: Ctrl) to talk
  * (Whisper), optionally hear the reply (TTS). Network and audio work runs in a
  * short-lived worker task, so the screen and keyboard stay responsive.
  *
@@ -72,7 +72,7 @@
        return key;
    }
    for (char c : key) {
        if (!isalnum((unsigned char)c) && c != '-' && c != '_') {
            problem = "The key contains a character OpenAI keys don't use (only letters, digits, - and _).";
            key.clear();
            break;
@@ -88,10 +88,10 @@
 void SSHTerminal::chat_load_settings()
 {
    nvs_handle_t h;
    if (settings_nvs::open("chat", NVS_READONLY, &h) != ESP_OK) {
        return;
    }
    char model[64];
    size_t len = sizeof(model);
    bool saved_model = nvs_get_str(h, "model", model, &len) == ESP_OK && model[0];
    if (saved_model) {
@@ -119,7 +119,7 @@
 void SSHTerminal::chat_save_settings()
 {
    nvs_handle_t h;
    esp_err_t err = settings_nvs::open("chat", NVS_READWRITE, &h);
    if (err == ESP_OK) {
        err = nvs_set_str(h, "model", chat_model.c_str());
        if (err == ESP_OK) {
@@ -213,7 +213,7 @@

 void SSHTerminal::chat_models_worker(void* param)
 {
    SSHTerminal* t = (SSHTerminal*)param;
    std::string key, error;
    openai::Models models;
    esp_err_t err = vault::get(KEY_ID, key);
@@ -383,7 +383,7 @@
        lv_obj_set_style_width(chat_view, 2, LV_PART_SCROLLBAR);
        lv_obj_add_event_cb(chat_view, scroll_end_cb, LV_EVENT_SCROLL_END, this);
        chat_follow = true;
        lv_obj_add_flag(terminal_output, LV_OBJ_FLAG_HIDDEN);
        lv_obj_move_foreground(side_panel);

        chat_add_bubble(BUBBLE_INFO, "ChatGPT (" + chat_model + ") - type, or " + board::HINT_TALK + " to talk.\n"
@@ -404,7 +404,7 @@
        lv_obj_delete(chat_view);
        chat_view = NULL;
    }
    lv_obj_clear_flag(terminal_output, LV_OBJ_FLAG_HIDDEN);
    update_input_display();
 }

@@ -465,7 +465,7 @@

 void SSHTerminal::chat_worker(void* param)
 {
    SSHTerminal* t = (SSHTerminal*)param;
    t->chat_job();
    t->chat_ui_banner("");
    t->chat_busy = false;
@@ -509,7 +509,7 @@
    }

    if (chat_job_voice) {
        int16_t* pcm = (int16_t*)heap_caps_malloc(MAX_RECORD_SAMPLES * 2, MALLOC_CAP_SPIRAM);
        if (!pcm || audio::mic_start() != ESP_OK) {
            chat_recording = false;
            heap_caps_free(pcm);
@@ -620,7 +620,7 @@
        openai::speak(key, tts_model, reply, [&](const uint8_t* data, size_t len) {
            // Keep whole 16-bit samples across chunk boundaries
            if (has_carry && len > 0) {
                uint8_t pair[2] = {carry, data[0]};
                audio::speaker_write(pair, 2);
                data++;
                len--;
@@ -771,9 +771,9 @@
                std::string problem = "No openai.key file at the top of the SD card.";
                for (const char* name : {"openai.key", "openai.key.txt", "openai.txt"}) {
                    std::string path = std::string(sdcard::MOUNT_POINT) + "/" + name;
                    FILE* f = fopen(path.c_str(), "rb");
                    if (f) {
                        char buf[1024];
                        size_t n = fread(buf, 1, sizeof(buf), f);
                        fclose(f);
                        std::string raw(buf, n);
@@ -841,7 +841,7 @@

        case WizardStep::ChatModel: {
            int n = !input.empty() && input.size() <= 2 && std::all_of(input.begin(), input.end(), ::isdigit)
                        ? atoi(input.c_str()) : -1;
            size_t shown = std::min(chat_models.size(), MODELS_SHOWN);
            if (n >= 1 && (size_t)n <= shown) {
                chat_model = chat_models[n - 1];

diff --git a/main/include/tab5_keymap.hpp b/main/include/tab5_keymap.hpp
@@ -3,14 +3,14 @@
  * Turns the Tab5 Keyboard's raw key presses and releases (row 0-4, column 0-13) into
  * SimplrSSH keys (input_events.hpp). The keyboard firmware reports only positions; this does
  * the legends, the Sym layer, Aa (hold = shift, tap = one capital, double tap = caps lock),
- * Ctrl codes, auto-repeat and Ctrl+Space push-to-talk. No ESP-IDF headers: tested on the host.
+ * Ctrl codes, auto-repeat and Ctrl push-to-talk. No ESP-IDF headers: tested on the host.
  *
  *   Up / Down             older / newer command, previous / next menu choice
  *   Left / Right          move the cursor; Sym+Left / Sym+Right: start / end of the line
  *   Sym+Up / Sym+Down     scroll the screen
  *   Del                   delete at the cursor
  *   Ctrl+letter           control code (Ctrl+C = 3 ...), also Ctrl+[ \ ] ^ _ /
- *   Ctrl+Space (hold)     push-to-talk in ChatGPT; held 1 s elsewhere: delete history entry
+ *   Ctrl (hold alone)     push-to-talk in ChatGPT; held 1 s elsewhere: delete history entry
  */
 
 #ifndef TAB5_KEYMAP_HPP
@@ -54,7 +54,8 @@ class Tab5Keymap
     uint32_t repeat_value = 0;
     uint32_t repeat_next_ms = 0;
 
-    bool talk_down = false;        // Ctrl+Space held
+    bool talk_down = false;        // Ctrl held, no other key pressed before HOLD_MS
+    bool talk_used = false;        // Another key pressed while talking
     bool talk_holding = false;     // HOLD_START sent
     uint32_t talk_pressed_ms = 0;
 

diff --git a/main/tab5_keymap.cpp b/main/tab5_keymap.cpp
@@ -32,7 +32,6 @@ static bool is_sym(int r, int c) { return at(r, c, 3, 0); }
 static bool is_aa(int r, int c) { return at(r, c, 3, 1); }
 static bool is_ctrl(int r, int c) { return at(r, c, 4, 0); }
 static bool is_alt(int r, int c) { return at(r, c, 4, 1); }
-static bool is_space(int r, int c) { return at(r, c, 4, 13); }
 
 // a - b >= 0 for wrapping millisecond counters
 static bool reached(uint32_t now, uint32_t when)
@@ -101,12 +100,35 @@ void Tab5Keymap::key_event(bool pressed, int row, int col, uint32_t now_ms)
     if (row < 0 || row >= ROWS || col < 0 || col >= COLS) {
         return;
     }
-    if (is_sym(row, col)) {
-        sym = pressed;
-        return;
-    }
     if (is_ctrl(row, col)) {
         ctrl = pressed;
+        if (pressed) {
+            // Ctrl on its own is push-to-talk once held for HOLD_MS (tick)
+            talk_down = true;
+            talk_holding = false;
+            talk_used = false;
+            talk_pressed_ms = now_ms;
+        } else if (talk_down) {
+            talk_down = false;
+            if (talk_holding) {
+                talk_holding = false;
+                // A long hold deletes a history entry outside ChatGPT: only when Ctrl was alone
+                bool long_hold = !talk_used && now_ms - talk_pressed_ms >= LONG_HOLD_MS;
+                push(KEY_EVENT | (long_hold ? INPUT_HOLD_END_LONG : INPUT_HOLD_END));
+            }
+        }
+        return;
+    }
+    if (pressed && talk_down) {
+        // Another key with Ctrl: a control code (Ctrl+C ...), not talking
+        if (talk_holding) {
+            talk_used = true;
+        } else {
+            talk_down = false;
+        }
+    }
+    if (is_sym(row, col)) {
+        sym = pressed;
         return;
     }
     if (is_alt(row, col)) {
@@ -141,25 +163,12 @@ void Tab5Keymap::key_event(bool pressed, int row, int col, uint32_t now_ms)
         if (id == repeat_key) {
             repeat_key = -1;
         }
-        if (is_space(row, col) && talk_down) {
-            talk_down = false;
-            if (talk_holding) {
-                talk_holding = false;
-                push(KEY_EVENT | (now_ms - talk_pressed_ms >= LONG_HOLD_MS ? INPUT_HOLD_END_LONG : INPUT_HOLD_END));
-            }
-        }
         return;
     }
 
     if (aa_down) {
         aa_used = true;
     }
-    if (is_space(row, col) && ctrl) {
-        talk_down = true;
-        talk_holding = false;
-        talk_pressed_ms = now_ms;
-        return;
-    }
     bool repeats = false;
     uint32_t value = translate(row, col, &repeats);
     one_shot = false;
@@ -191,6 +200,6 @@ void Tab5Keymap::reset()
         push(KEY_EVENT | INPUT_HOLD_END);   // Stop a recording in progress
     }
     sym = ctrl = aa_down = aa_used = one_shot = caps_lock = false;
-    talk_down = talk_holding = false;
+    talk_down = talk_holding = talk_used = false;
     repeat_key = -1;
 }
diff --git a/sdkconfig.defaults b/sdkconfig.defaults
@@ -12,6 +12,16 @@ CONFIG_LWIP_IPV6=n
 # libssh2 protocol tracing is never used in production and could log session data
 CONFIG_LIBSSH2_DEBUG_ENABLE=n
 
+# --- Build and boot (both boards) ---------------------------------------------
+# app_main mounts the SD card, starts the display and touch and builds the terminal screen
+# before handing over to keypad_task; the 3.5 KB default overflows. Freed when it returns.
+CONFIG_ESP_MAIN_TASK_STACK_SIZE=12288
+# Optimize for speed (TLS, SSH crypto, rendering); assertions compiled out
+CONFIG_COMPILER_OPTIMIZATION_PERF=y
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_DISABLE=y
+# Problems only in the log (AI_RULES.md: ESP_LOGI sparingly)
+CONFIG_LOG_DEFAULT_LEVEL_WARN=y
+
 # --- Internal RAM: move bulk buffers to PSRAM --------------------------------
 # WiFi/LWIP buffers in PSRAM when possible
 CONFIG_SPIRAM_TRY_ALLOCATE_WIFI_LWIP=y