change to 4.2 inch screen

CMakeLists.txt

@@ -44,6 +44,8 @@ if (TARGET tinyusb_host)
                 command_processor.cpp
                 epaper_manager.cpp
                 wifi_manager.cpp
+                tcp_debug.cpp
+                keyboard_stdio.cpp
                 )
 
     add_subdirectory(pico-ssd1306 commands)

epaper_manager.cpp

@@ -1,5 +1,6 @@
 #include "epaper_manager.h"
 #include "wifi_manager.h"
+#include "tcp_debug.h"
 #include "pico/stdlib.h"
 #include "pico/multicore.h"
 #include "pico/flash.h"
@@ -11,16 +12,15 @@
 // e-Paper library includes
 extern "C" {
     #include "DEV_Config.h"
-    #include "EPD_7in5b_V2.h"
+    #include "EPD_4in2_V2.h"
     #include "GUI_Paint.h"
 }
 
 // e-Paper display buffers
 static UBYTE *g_epd_image = NULL;  // Black image buffer
-static UBYTE *g_epd_red = NULL;    // Red image buffer
 
 // Entry list for display
-#define MAX_ENTRIES 15
+#define MAX_ENTRIES 10
 #define ENTRY_LENGTH 64
 typedef struct {
     char entries[MAX_ENTRIES][ENTRY_LENGTH];
@@ -48,7 +48,7 @@ typedef struct {
 } DisplayMessage;
 
 static void init_epaper_display() {
-    printf("[Core 1] Initializing 7.5\" e-Paper display (B V2)...\r\n");
+    printf("[Core 1] Initializing 4.2\" e-Paper display (V2)...\r\n");
     
     // Initialize the hardware
     if (DEV_Module_Init() != 0) {
@@ -57,55 +57,51 @@ static void init_epaper_display() {
     }
     
     // Initialize the display
-    printf("[Core 1] EPD_7IN5B_V2_Init()\r\n");
-    EPD_7IN5B_V2_Init_Fast();
-    printf("[Core 1] EPD_7IN5B_V2_Clear()\r\n");
+    printf("[Core 1] EPD_4IN2_V2_Init_Fast()\r\n");
+    EPD_4IN2_V2_Init();
+    printf("[Core 1] EPD_4IN2_V2_Clear()\r\n");
+    EPD_4IN2_V2_Clear();
     
-    // Create image buffers for black and red content
-    // 7.5" display: 800x480, 8 pixels per byte, so (800/8) * 480 = 48000 bytes each
-    UWORD imagesize = (EPD_7IN5B_V2_WIDTH / 8) * EPD_7IN5B_V2_HEIGHT;
+    // Create image buffers for black content
+    // 4.2" display: 400x300, 8 pixels per byte
+    UWORD imagesize = ((EPD_4IN2_V2_WIDTH % 8 == 0)? (EPD_4IN2_V2_WIDTH / 8 ): (EPD_4IN2_V2_WIDTH / 8 + 1)) * EPD_4IN2_V2_HEIGHT;
     
     g_epd_image = (UBYTE *)malloc(imagesize);
-    g_epd_red = (UBYTE *)malloc(imagesize);
     
-    if (g_epd_image == NULL || g_epd_red == NULL) {
+    if (g_epd_image == NULL) {
         printf("[Core 1] Failed to allocate memory for e-Paper image buffers!\r\n");
         return;
     }
     
-    // Initialize red buffer to all white (0xFF = no red pixels)
-    for (UWORD i = 0; i < imagesize; i++) {
-        g_epd_red[i] = 0xFF;
-    }
-    
     // Setup paint buffer for black content
     printf("[Core 1] White background\r\n");
-    Paint_NewImage(g_epd_image, EPD_7IN5B_V2_WIDTH, EPD_7IN5B_V2_HEIGHT, 0, WHITE);
+    Paint_NewImage(g_epd_image, EPD_4IN2_V2_WIDTH, EPD_4IN2_V2_HEIGHT, 0, WHITE);
     Paint_SelectImage(g_epd_image);
     Paint_Clear(WHITE);
-    
-    // Draw header
-    EPD_7IN5B_V2_Init_Part();
-    EPD_7IN5B_V2_Display_Partial(g_epd_image, 0, 0, EPD_7IN5B_V2_WIDTH, EPD_7IN5B_V2_HEIGHT);
-    EPD_7IN5B_V2_Display_Partial(g_epd_image, 0, 0, EPD_7IN5B_V2_WIDTH, EPD_7IN5B_V2_HEIGHT);
-    EPD_7IN5B_V2_Display_Partial(g_epd_image, 0, 0, EPD_7IN5B_V2_WIDTH, EPD_7IN5B_V2_HEIGHT);
 
     printf("[Core 1] Trying to connect to wifi\r\n");
     bool connected = wifi_try_auto_connect();
     printf("[Core 1] Connected: %d\r\n", connected);
     
+    if (connected) {
+        tcp_debug_init();
+    }
 
-    Paint_SelectImage(g_epd_red);
+    Paint_SelectImage(g_epd_image);
     printf("[Core 1] Drawing header\r\n");
     if (connected) {
-        Paint_DrawString_EN(10, 10, "What's new today: ...", &Font24, WHITE, RED);
+        char header_text[64];
+        const char* ip = wifi_get_ip();
+        snprintf(header_text, sizeof(header_text), "IP: %s", ip ? ip : "Unknown");
+        Paint_DrawString_EN(10, 10, header_text, &Font24, WHITE, BLACK);
     } else {
-        Paint_DrawString_EN(10, 10, "What's new today:", &Font24, WHITE, RED);
+        Paint_DrawString_EN(10, 10, "What's new today:", &Font24, WHITE, BLACK);
     }
     
     
-    // Display the image with both black and red buffers
-    EPD_7IN5B_V2_Display_Partial(g_epd_red, 0, 0, EPD_7IN5B_V2_WIDTH, EPD_7IN5B_V2_HEIGHT);
+    // Display the image
+    EPD_4IN2_V2_PartialDisplay(g_epd_image, 0, 0, EPD_4IN2_V2_WIDTH, 40);
+    // EPD_4IN2_V2_Display_Fast(g_epd_image);
     
     printf("[Core 1] e-Paper display ready!\r\n");
 }
@@ -126,7 +122,7 @@ static void core1_display_init() {
     printf("[Core 1] Display ready, waiting for update messages...\n");
     
     // Initialize for partial refresh on second call
-    EPD_7IN5B_V2_Init_Part();
+    // EPD_4IN2_V2_Init_Fast(Seconds_1S); // Already done in init
     
     // Core 1 main loop: handle display updates via Queue
     while (true) {
@@ -137,15 +133,15 @@ static void core1_display_init() {
             // Drain Queue to get the latest message
             DisplayMessage *next_msg;
             while (queue_try_remove(&g_display_queue, &next_msg)) {
-                 printf("[Core 1] Skipping intermediate update\n");
+                 // printf("[Core 1] Skipping intermediate update\n");
                  free(msg); // Free the stale message
                  msg = next_msg;
             }
             
-            printf("[Core 1] Updating display with %d entries\n", msg->entries.count);
+            // printf("[Core 1] Updating display with %d entries\n", msg->entries.count);
             
             // Update the e-Paper display
-            if (g_epd_image != NULL && g_epd_red != NULL) {
+            if (g_epd_image != NULL) {
                 // For partial refresh, only clear the text area
                 UWORD y_start = msg->ystart;
                 UWORD y_end = msg->yend;
@@ -154,13 +150,14 @@ static void core1_display_init() {
                 Paint_Clear(WHITE);
                 
                 // Calculate offset for partial refresh
-                UBYTE *image_ptr = g_epd_image + (msg->ystart * (EPD_7IN5B_V2_WIDTH / 8));
+                // UBYTE *image_ptr = g_epd_image + (msg->ystart * (EPD_4IN2_V2_WIDTH / 8));
 
                 if(!msg->use_partial){
                     // for loop 5 times display white partial
+                    Paint_Clear(WHITE);
                     int i = 0;
                     for(i = 0; i < 1; i++){
-                        EPD_7IN5B_V2_Display_Partial(image_ptr, msg->xstart, msg->ystart, msg->xend, msg->yend);
+                        EPD_4IN2_V2_PartialDisplay(g_epd_image, 0, 0, 400, 300);
                     }
                 }
                 
@@ -169,7 +166,7 @@ static void core1_display_init() {
                 // paint only the last 10 entries
                 int start_index = msg->entries.count > 10 ? msg->entries.count - 10 : 0;
                 for (int i = start_index; i < msg->entries.count; i++) {
-                    if (y_pos + 25 < 480) {  //Don't draw beyond screen
+                    if (y_pos + 25 < 300) {  //Don't draw beyond screen
                         Paint_DrawString_EN(20, 50 + i*25, msg->entries.entries[i], &Font16, WHITE, BLACK);
                         y_pos += 25;  // Space between entries
                     } else {
@@ -177,8 +174,8 @@ static void core1_display_init() {
                     }
                 }
                 // Use partial or full refresh
-                printf("[Core 1] Using partial refresh\n");
-                EPD_7IN5B_V2_Display_Partial(image_ptr, msg->xstart, msg->ystart, msg->xend, msg->yend);
+                // printf("[Core 1] Using partial refresh\n");
+                EPD_4IN2_V2_PartialDisplay(g_epd_image, 0, 0, 400, 300);
             }
             
             // Free the message (it was allocated by core 0)
@@ -235,13 +232,13 @@ void epaper_send_update(const char *entry, bool finish_line) {
         // Full text area refresh
         msg->xstart = 0;
         msg->ystart = 50;      // Start below the header
-        msg->xend = 800;       // Full width
-        msg->yend = 480;       // Full height from header onwards
+        msg->xend = EPD_4IN2_V2_WIDTH;       // Full width
+        msg->yend = EPD_4IN2_V2_HEIGHT;       // Full height from header onwards
     } else {
         // Partial refresh of ONLY the current line
         msg->xstart = 0;
         msg->ystart = 50 + (g_entry_list.count * 25);
-        msg->xend = 800;
+        msg->xend = EPD_4IN2_V2_WIDTH;
         msg->yend = msg->ystart + 25;
     }
     

hello_usb.cpp

@@ -22,13 +22,19 @@
 // Holds last echoed line for display
 static char g_last_echo[128] = "";
 
-// Global DisplayManager pointer
-static DisplayManager* g_display_manager = nullptr;
+#include "command_processor.h"
+#include "epaper_manager.h"
+#include "wifi_manager.h"
+#include "tcp_debug.h"
+#include "keyboard_stdio.h"
 
-// Keyboard buffer
+// Global display manager instance
+DisplayManager* g_display_manager = nullptr;
+
+// Command line buffer
 #define MAX_INPUT_LEN 64
-static char g_input_buffer[MAX_INPUT_LEN];
-static int g_buffer_index = 0;
+static char g_cmd_buffer[MAX_INPUT_LEN];
+static int g_cmd_index = 0;
 
 static bool execute_command(CommandAction action, const char* input) {
     switch (action) {
@@ -75,6 +81,7 @@ static bool execute_command(CommandAction action, const char* input) {
                     epaper_send_update(err_msg, true);
                 } else {
                     epaper_send_update("Connected!", true);
+                    tcp_debug_init();
                 }
             } else {
                 if (g_display_manager) g_display_manager->refresh("Connection Failed", nullptr);
@@ -103,62 +110,8 @@ static bool execute_command(CommandAction action, const char* input) {
 static void process_kbd_report(hid_keyboard_report_t const *report) {
     KeyEvent event;
     if (parse_keyboard_report(report, &event)) {
-        if (event.is_backspace) {
-            if (g_buffer_index > 0) {
-                printf("\b \b");
-                g_buffer_index--;
-                g_input_buffer[g_buffer_index] = '\0';
-                
-                // Update OLED
-                if (g_display_manager) g_display_manager->refresh(g_input_buffer, g_last_echo);
-                
-                // Update e-Paper (in-place)
-                epaper_send_update(g_input_buffer, false);
-            }
-        } else if (event.is_enter) {
-            printf("\n");
-            
-            // Always commit the input line to e-Paper so commands are visible
-            if (g_buffer_index > 0) {
-                epaper_send_update(g_input_buffer, true);
-            }
-            
-            CommandAction action = parse_command(g_input_buffer);
-            if (execute_command(action, g_input_buffer)) {
-                // Command handled
-                if (g_display_manager) {
-                    g_display_manager->set_last_echo("Command Executed");
-                    g_display_manager->refresh("", "Command Executed");
-                }
-            } else {
-                // Not a command, just text (already committed to e-Paper above)
-                
-                // Save to last echo
-                strncpy(g_last_echo, g_input_buffer, sizeof(g_last_echo) - 1);
-                g_last_echo[sizeof(g_last_echo) - 1] = '\0';
-                
-                // Update OLED
-                if (g_display_manager) {
-                    g_display_manager->set_last_echo(g_last_echo);
-                    g_display_manager->refresh("", g_last_echo);
-                }
-            }
-            
-            // Clear buffer
-            g_buffer_index = 0;
-            g_input_buffer[0] = '\0';
-        } else if (event.is_printable) {
-            printf("%c", event.ascii);
-            if (g_buffer_index < MAX_INPUT_LEN - 1) {
-                g_input_buffer[g_buffer_index++] = event.ascii;
-                g_input_buffer[g_buffer_index] = '\0';
-                
-                // Update OLED
-                if (g_display_manager) g_display_manager->refresh(g_input_buffer, g_last_echo);
-                
-                // Update e-Paper on every keystroke
-                epaper_send_update(g_input_buffer, false);
-            }
+        if (event.ascii) {
+            keyboard_stdio_push_char(event.ascii);
         }
     }
 }
@@ -200,8 +153,8 @@ void tuh_hid_umount_cb(uint8_t dev_addr, uint8_t instance) {
     g_keyboard_mounted = false;
     
     // Reset input buffer
-    g_buffer_index = 0;
-    g_input_buffer[0] = '\0';
+    g_cmd_index = 0;
+    g_cmd_buffer[0] = '\0';
 
     if (g_display_manager) {
         g_display_manager->refresh("Waiting for Keyboard", nullptr);
@@ -221,8 +174,69 @@ void tuh_hid_report_received_cb(uint8_t dev_addr, uint8_t instance, uint8_t cons
     }
 }
 
+static void process_input_char(char c) {
+    if (c == '\b' || c == 127) {
+        if (g_cmd_index > 0) {
+            printf("\b \b");
+            g_cmd_index--;
+            g_cmd_buffer[g_cmd_index] = '\0';
+            
+            // Update OLED
+            if (g_display_manager) g_display_manager->refresh(g_cmd_buffer, g_last_echo);
+            
+            // Update e-Paper (in-place)
+            epaper_send_update(g_cmd_buffer, false);
+        }
+    } else if (c == '\r' || c == '\n') {
+        printf("\n");
+        
+        // Always commit the input line to e-Paper so commands are visible
+        if (g_cmd_index > 0) {
+            epaper_send_update(g_cmd_buffer, true);
+        }
+        
+        CommandAction action = parse_command(g_cmd_buffer);
+        if (execute_command(action, g_cmd_buffer)) {
+            // Command handled
+            if (g_display_manager) {
+                g_display_manager->set_last_echo("Command Executed");
+                g_display_manager->refresh("", "Command Executed");
+            }
+        } else {
+            // Not a command, just text (already committed to e-Paper above)
+            
+            // Save to last echo
+            strncpy(g_last_echo, g_cmd_buffer, sizeof(g_last_echo) - 1);
+            g_last_echo[sizeof(g_last_echo) - 1] = '\0';
+            
+            // Update OLED
+            if (g_display_manager) {
+                g_display_manager->set_last_echo(g_last_echo);
+                g_display_manager->refresh("", g_last_echo);
+            }
+        }
+        
+        // Clear buffer
+        g_cmd_index = 0;
+        g_cmd_buffer[0] = '\0';
+    } else {
+        printf("%c", c);
+        if (g_cmd_index < MAX_INPUT_LEN - 1) {
+            g_cmd_buffer[g_cmd_index++] = c;
+            g_cmd_buffer[g_cmd_index] = '\0';
+            
+            // Update OLED
+            if (g_display_manager) g_display_manager->refresh(g_cmd_buffer, g_last_echo);
+            
+            // Update e-Paper on every keystroke
+            epaper_send_update(g_cmd_buffer, false);
+        }
+    }
+}
+
 int main() {
     stdio_init_all();
+    keyboard_stdio_init();
     sleep_ms(3000); // Give time for power to settle and serial to connect
     printf("System Booting...\n");
     
@@ -241,6 +255,11 @@ int main() {
     while (true) {
         tuh_task();
         
+        int c = getchar_timeout_us(0);
+        if (c != PICO_ERROR_TIMEOUT) {
+            process_input_char((char)c);
+        }
+
         uint32_t now = to_ms_since_boot(get_absolute_time());
         if (now - last_print > 5000) {
             printf("Heartbeat: %u, Mounted: %d\n", now, g_keyboard_mounted);

keyboard_stdio.cpp

@@ -0,0 +1,46 @@
+#include "keyboard_stdio.h"
+#include "pico/stdio/driver.h"
+#include "pico/sync.h"
+
+#define KBD_BUF_SIZE 128
+
+// Circular buffer for keyboard input
+static char kbd_buf[KBD_BUF_SIZE];
+static volatile int write_idx = 0;
+static volatile int read_idx = 0;
+static critical_section_t kbd_crit;
+
+void keyboard_stdio_push_char(char c) {
+    critical_section_enter_blocking(&kbd_crit);
+    int next_write = (write_idx + 1) % KBD_BUF_SIZE;
+    if (next_write != read_idx) { // Only write if not full
+        kbd_buf[write_idx] = c;
+        write_idx = next_write;
+    }
+    critical_section_exit(&kbd_crit);
+}
+
+static int keyboard_in_chars(char *buf, int len) {
+    int count = 0;
+    critical_section_enter_blocking(&kbd_crit);
+    while (count < len && read_idx != write_idx) {
+        buf[count++] = kbd_buf[read_idx];
+        read_idx = (read_idx + 1) % KBD_BUF_SIZE;
+    }
+    critical_section_exit(&kbd_crit);
+    return count > 0 ? count : PICO_ERROR_NO_DATA;
+}
+
+static stdio_driver_t kbd_driver = {
+    .out_chars = NULL,
+    .out_flush = NULL,
+    .in_chars = keyboard_in_chars,
+#if PICO_STDIO_ENABLE_CRLF_SUPPORT
+    .crlf_enabled = false
+#endif
+};
+
+void keyboard_stdio_init(void) {
+    critical_section_init(&kbd_crit);
+    stdio_set_driver_enabled(&kbd_driver, true);
+}

keyboard_stdio.h

@@ -0,0 +1,18 @@
+#ifndef KEYBOARD_STDIO_H
+#define KEYBOARD_STDIO_H
+
+#include <stdbool.h>
+
+/**
+ * Initializes the keyboard stdio driver.
+ * This allows standard C input functions (getchar, scanf, etc.) to read from the USB keyboard.
+ */
+void keyboard_stdio_init(void);
+
+/**
+ * Pushes a character into the keyboard input buffer.
+ * This should be called by the USB HID report handler.
+ */
+void keyboard_stdio_push_char(char c);
+
+#endif

tcp_debug.cpp

@@ -0,0 +1,177 @@
+#include "tcp_debug.h"
+#include "pico/cyw43_arch.h"
+#include "lwip/tcp.h"
+#include "pico/stdio/driver.h"
+#include "pico/sync.h"
+#include <string.h>
+#include <stdio.h>
+
+#define TCP_PORT 4242
+#define DEBUG_BUF_SIZE 2048
+#define TCP_IN_BUF_SIZE 128
+
+// Circular buffer for debug output
+static char debug_buf[DEBUG_BUF_SIZE];
+static volatile int write_idx = 0;
+static volatile int read_idx = 0;
+
+// Circular buffer for TCP input
+static char tcp_in_buf[TCP_IN_BUF_SIZE];
+static volatile int in_write_idx = 0;
+static volatile int in_read_idx = 0;
+static critical_section_t tcp_in_crit;
+
+static struct tcp_pcb *server_pcb = NULL;
+static struct tcp_pcb *client_pcb = NULL;
+
+// Helper to write to buffer
+static void buffer_write(const char *data, int len) {
+    for (int i = 0; i < len; i++) {
+        int next_write = (write_idx + 1) % DEBUG_BUF_SIZE;
+        if (next_write != read_idx) { // Only write if not full
+            debug_buf[write_idx] = data[i];
+            write_idx = next_write;
+        }
+    }
+}
+
+// stdio driver callback
+static void tcp_out_chars(const char *buf, int len) {
+    // Handle CRLF conversion manually if needed, or just write raw
+    // The issue is likely that \n is sent without \r, causing "staircase" effect in raw terminals
+    for (int i = 0; i < len; i++) {
+        if (buf[i] == '\n') {
+            char cr = '\r';
+            buffer_write(&cr, 1);
+        }
+        buffer_write(&buf[i], 1);
+    }
+}
+
+static int tcp_in_chars(char *buf, int len) {
+    int count = 0;
+    critical_section_enter_blocking(&tcp_in_crit);
+    while (count < len && in_read_idx != in_write_idx) {
+        buf[count++] = tcp_in_buf[in_read_idx];
+        in_read_idx = (in_read_idx + 1) % TCP_IN_BUF_SIZE;
+    }
+    critical_section_exit(&tcp_in_crit);
+    return count > 0 ? count : PICO_ERROR_NO_DATA;
+}
+
+static stdio_driver_t tcp_driver = {
+    .out_chars = tcp_out_chars,
+    .out_flush = NULL,
+    .in_chars = tcp_in_chars,
+#if PICO_STDIO_ENABLE_CRLF_SUPPORT
+    .crlf_enabled = false
+#endif
+};
+
+// TCP callbacks
+static err_t tcp_server_poll(void *arg, struct tcp_pcb *tpcb) {
+    if (tpcb != client_pcb) return ERR_OK;
+
+    // Check if there is data in the ring buffer to send
+    if (write_idx != read_idx) {
+        int len_to_send = 0;
+        char send_buf[256]; // Temporary buffer for one TCP write chunk
+        
+        // Copy from ring buffer to linear buffer
+        while (write_idx != read_idx && len_to_send < sizeof(send_buf)) {
+            send_buf[len_to_send++] = debug_buf[read_idx];
+            read_idx = (read_idx + 1) % DEBUG_BUF_SIZE;
+        }
+
+        if (len_to_send > 0) {
+            err_t err = tcp_write(tpcb, send_buf, len_to_send, TCP_WRITE_FLAG_COPY);
+            if (err == ERR_OK) {
+                tcp_output(tpcb);
+            } else {
+                // If write failed (e.g. buffer full), rewind read_idx (simple retry logic)
+                // Note: This is a simplification. In a real robust system we might drop data or handle partial writes.
+                // For now, we just lose the data if TCP is full to avoid blocking the system.
+            }
+        }
+    }
+    return ERR_OK;
+}
+
+static err_t tcp_server_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err) {
+    if (!p) {
+        tcp_close(tpcb);
+        client_pcb = NULL;
+        printf("TCP debug client disconnected\n");
+        return ERR_OK;
+    }
+    
+    // Process received data into input buffer
+    if (p->tot_len > 0) {
+        critical_section_enter_blocking(&tcp_in_crit);
+        struct pbuf *q = p;
+        while (q != NULL) {
+            char *data = (char *)q->payload;
+            for (int i = 0; i < q->len; i++) {
+                int next_write = (in_write_idx + 1) % TCP_IN_BUF_SIZE;
+                if (next_write != in_read_idx) {
+                    tcp_in_buf[in_write_idx] = data[i];
+                    in_write_idx = next_write;
+                }
+            }
+            q = q->next;
+        }
+        critical_section_exit(&tcp_in_crit);
+        tcp_recved(tpcb, p->tot_len);
+    }
+    
+    pbuf_free(p);
+    return ERR_OK;
+}
+
+static err_t tcp_server_accept(void *arg, struct tcp_pcb *newpcb, err_t err) {
+    if (client_pcb) {
+        // Already have a client, reject or close old?
+        // Let's close the old one and accept the new one (last one wins)
+        tcp_abort(client_pcb);
+    }
+    
+    client_pcb = newpcb;
+    tcp_recv(newpcb, tcp_server_recv);
+    tcp_poll(newpcb, tcp_server_poll, 1); // Poll every 500ms (coarse grain) -> actually arg is interval in 500ms steps? 
+    // Wait, poll interval is passed to tcp_poll. 1 means every 500ms.
+    // We might want faster polling for debug output.
+    // But we can't poll faster than the lwIP timer.
+    // However, we can also trigger writes from the main loop if we wanted, but polling is safer for threading.
+    
+    printf("TCP debug client connected\n");
+    return ERR_OK;
+}
+
+bool tcp_debug_init(void) {
+    if (server_pcb) return true;
+
+    critical_section_init(&tcp_in_crit);
+
+    // Register stdio driver
+    stdio_set_driver_enabled(&tcp_driver, true);
+
+    cyw43_arch_lwip_begin();
+    server_pcb = tcp_new_ip_type(IPADDR_TYPE_ANY);
+    if (!server_pcb) {
+        cyw43_arch_lwip_end();
+        return false;
+    }
+
+    err_t err = tcp_bind(server_pcb, IP_ANY_TYPE, TCP_PORT);
+    if (err != ERR_OK) {
+        cyw43_arch_lwip_end();
+        return false;
+    }
+
+    server_pcb = tcp_listen(server_pcb);
+    tcp_accept(server_pcb, tcp_server_accept);
+    cyw43_arch_lwip_end();
+
+    printf("TCP debug server listening on port %d\n", TCP_PORT);
+    return true;
+}

tcp_debug.h

@@ -0,0 +1,13 @@
+#ifndef TCP_DEBUG_H
+#define TCP_DEBUG_H
+
+#include <stdbool.h>
+
+/**
+ * Initializes the TCP debug server on port 4242.
+ * Registers a stdio driver that redirects printf output to connected TCP clients.
+ * Returns true on success.
+ */
+bool tcp_debug_init(void);
+
+#endif