Stabilize USB control firmware

App/Core/app_core.c

@@ -97,6 +97,14 @@ typedef struct app_context_t {
     /* Written by app_uart_protocol_feed_byte() and reset helpers. Read by UART IRQ path and timeout logic. Purpose: incremental UART parser state. */
     app_uart_protocol_parser_t parser;
 
+    /*
+     * Written by USART IRQ after a complete packet is parsed.
+     * Consumed by app_run_once() so device, SPI, delay, and SD-card work
+     * stays out of interrupt context.
+     */
+    volatile uint8_t pending_uart_packet_ready;
+    app_packet_t pending_uart_packet;
+
     /* Written by app_capture_live_frame() and telemetry helpers. Read by telemetry finalisation/serialisation. Purpose: canonical structured telemetry snapshot. */
     telemetry_frame_t telemetry;
 
@@ -157,6 +165,7 @@ static void app_handle_ad9102_wave_control_packet(const app_packet_t *packet);
 static void app_handle_ad9102_wave_data_packet(const app_packet_t *packet);
 static void app_handle_profile_save_data_packet(const app_packet_t *packet);
 static void app_process_work_mode(void);
+static void app_handle_pending_uart_packet(void);
 static void app_flush_tx_request(void);
 static void app_check_uart_timeout(void);
 static void app_handle_pending_event(void);
@@ -197,6 +206,7 @@ static void app_reset_runtime_state(bool reset_ticks)
 
     telemetry_reset(&g_app.telemetry);
     app_uart_protocol_reset(&g_app.parser);
+    g_app.pending_uart_packet_ready = 0u;
     uart_transport_reset();
 
     if (reset_ticks)
@@ -633,6 +643,12 @@ static bool app_handle_profile_boot(void)
     FILINFO profile_index_info;
     FRESULT profile_index_result;
 
+    /* Legacy behaviour: saved SD startup data is used only without USB. */
+    if (board_io_is_usb_connected())
+    {
+        return false;
+    }
+
     app_set_boot_diag(APP_BOOT_DIAG_STARTED);
 
     if (!storage_sd_is_available())
@@ -1224,6 +1240,31 @@ static void app_process_work_mode(void)
     }
 }
 
+static void app_handle_pending_uart_packet(void)
+{
+    app_packet_t packet;
+    uint8_t packet_ready = 0u;
+
+    if (g_app.pending_uart_packet_ready == 0u)
+    {
+        return;
+    }
+
+    __disable_irq();
+    if (g_app.pending_uart_packet_ready != 0u)
+    {
+        packet = g_app.pending_uart_packet;
+        g_app.pending_uart_packet_ready = 0u;
+        packet_ready = 1u;
+    }
+    __enable_irq();
+
+    if (packet_ready != 0u)
+    {
+        app_handle_packet(&packet);
+    }
+}
+
 static void app_flush_tx_request(void)
 {
     switch (g_app.tx_request)
@@ -1304,7 +1345,10 @@ void app_init(void)
 
     app_initialise_default_configuration();
     app_reset_runtime_state(true);
-    ui_status_init();
+    if (!board_io_is_usb_connected())
+    {
+        ui_status_init();
+    }
     app_set_mode(APP_MODE_IDLE);
     g_app.resume_mode = APP_MODE_IDLE;
     app_set_boot_diag(APP_BOOT_DIAG_NONE);
@@ -1330,9 +1374,16 @@ void app_run_once(void)
     app_event_t ui_event;
 
     app_ensure_uart_rx_enabled();
+
+    if (g_app.mode == APP_MODE_WORK)
+    {
+        app_process_work_mode();
+    }
+
     ui_event = ui_status_poll_event(g_app.tick_10ms);
     app_post_event(ui_event);
 
+    app_handle_pending_uart_packet();
     app_handle_pending_event();
 
     switch (g_app.mode)
@@ -1389,7 +1440,15 @@ void app_on_uart_byte(uint8_t byte)
     }
     else if (result == APP_PROTOCOL_FEED_PACKET_READY)
     {
-        app_handle_packet(&packet);
+        if (g_app.pending_uart_packet_ready == 0u)
+        {
+            g_app.pending_uart_packet = packet;
+            g_app.pending_uart_packet_ready = 1u;
+        }
+        else
+        {
+            app_set_error(APP_STATUS_FLAG_UART_ERROR);
+        }
     }
 }
 

App/Devices/adc_mux.c

@@ -40,6 +40,10 @@ uint16_t adc_mux_read_external_channel(uint8_t channel_index)
             ++delay_counter;
         }
         LL_SPI_Disable(SPI4);
+        while (delay_counter < 500u)
+        {
+            ++delay_counter;
+        }
         HAL_GPIO_WritePin(ADC_MPD1_CS_GPIO_Port, ADC_MPD1_CS_Pin, GPIO_PIN_SET);
         result = LL_SPI_ReceiveData16(SPI4);
     }
@@ -58,6 +62,10 @@ uint16_t adc_mux_read_external_channel(uint8_t channel_index)
             ++delay_counter;
         }
         LL_SPI_Disable(SPI5);
+        while (delay_counter < 500u)
+        {
+            ++delay_counter;
+        }
         HAL_GPIO_WritePin(ADC_MPD2_CS_GPIO_Port, ADC_MPD2_CS_Pin, GPIO_PIN_SET);
         result = LL_SPI_ReceiveData16(SPI5);
     }
@@ -76,6 +84,10 @@ uint16_t adc_mux_read_external_channel(uint8_t channel_index)
             ++delay_counter;
         }
         LL_SPI_Disable(SPI4);
+        while (delay_counter < 500u)
+        {
+            ++delay_counter;
+        }
         HAL_GPIO_WritePin(ADC_ThrLD1_CS_GPIO_Port, ADC_ThrLD1_CS_Pin, GPIO_PIN_SET);
         result = LL_SPI_ReceiveData16(SPI4);
     }
@@ -94,6 +106,10 @@ uint16_t adc_mux_read_external_channel(uint8_t channel_index)
             ++delay_counter;
         }
         LL_SPI_Disable(SPI5);
+        while (delay_counter < 500u)
+        {
+            ++delay_counter;
+        }
         HAL_GPIO_WritePin(ADC_ThrLD2_CS_GPIO_Port, ADC_ThrLD2_CS_Pin, GPIO_PIN_SET);
         result = LL_SPI_ReceiveData16(SPI5);
     }

App/Services/ui_status.c

@@ -112,9 +112,16 @@ void ui_status_set_error(uint8_t error_flags)
 
 app_event_t ui_status_poll_event(uint32_t tick_10ms)
 {
-    bool raw_pressed = board_io_is_standalone_ui_button_pressed();
+    bool raw_pressed;
     app_event_t event = APP_EVENT_NONE;
 
+    if (g_initialised == 0u)
+    {
+        return APP_EVENT_NONE;
+    }
+
+    raw_pressed = board_io_is_standalone_ui_button_pressed();
+
     if (raw_pressed != g_button.raw_pressed)
     {
         g_button.raw_pressed = raw_pressed;