fix wifi & flash + eink screen on core 1, by using queue

CMakeLists.txt

@@ -62,7 +62,7 @@ if (TARGET tinyusb_host)
     )
 
     # pull in common dependencies
-    target_link_libraries(hello_usb pico_stdlib pico_ssd1306 hardware_i2c Config ePaper GUI Fonts hardware_spi pico_multicore tinyusb_host tinyusb_board pico_cyw43_arch_lwip_threadsafe_background)
+    target_link_libraries(hello_usb pico_stdlib pico_ssd1306 hardware_i2c Config ePaper GUI Fonts hardware_spi pico_multicore pico_flash tinyusb_host tinyusb_board pico_cyw43_arch_lwip_threadsafe_background)
 
     # enable usb output, disable uart output
     pico_enable_stdio_usb(hello_usb 0)

epaper_manager.cpp

@@ -2,6 +2,8 @@
 #include "wifi_manager.h"
 #include "pico/stdlib.h"
 #include "pico/multicore.h"
+#include "pico/flash.h"
+#include "pico/util/queue.h"
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -31,6 +33,10 @@ static bool g_force_full_refresh = false;  // Flag to force full refresh when li
 // Synchronization flag for multicore initialization
 static volatile bool g_display_ready = false;
 
+// Queue for display messages (replacing raw FIFO to avoid conflict with flash_safe_execute)
+static queue_t g_display_queue;
+#define QUEUE_LENGTH 8
+
 // Display update message structure for inter-core communication
 typedef struct {
     EntryList entries;
@@ -84,9 +90,18 @@ static void init_epaper_display() {
     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("Trying to connect to wifi\r\n");
+    bool connected = wifi_try_auto_connect();
+    
+
     Paint_SelectImage(g_epd_red);
     printf("Drawing header\r\n");
+    if (connected) {
+        Paint_DrawString_EN(10, 10, "What's new today: ...", &Font24, WHITE, RED);
+    } else {
         Paint_DrawString_EN(10, 10, "What's new today:", &Font24, WHITE, RED);
+    }
+    
     
     // 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);
@@ -98,6 +113,9 @@ static void init_epaper_display() {
  * Core 1 function: Runs display initialization and update handling
  */
 static void core1_display_init() {
+    // Initialize flash safe execute support for this core
+    flash_safe_execute_core_init();
+
     // Initialize WiFi on Core 1 so IRQs are handled here
     wifi_init();
 
@@ -109,20 +127,18 @@ static void core1_display_init() {
     // Initialize for partial refresh on second call
     EPD_7IN5B_V2_Init_Part();
     
-    // Core 1 main loop: handle display updates via FIFO
+    // Core 1 main loop: handle display updates via Queue
     while (true) {
-        // Check if there's a message from core 0
+        DisplayMessage *msg;
-        if (multicore_fifo_rvalid()) {
+        // Check if there's a message in the queue
-            // Read the message pointer
+        if (queue_try_remove(&g_display_queue, &msg)) {
-            uint32_t msg_addr = multicore_fifo_pop_blocking();
-            DisplayMessage *msg = (DisplayMessage *)msg_addr;
             
-            // Drain FIFO to get the latest message
+            // Drain Queue to get the latest message
-            while (multicore_fifo_rvalid()) {
+            DisplayMessage *next_msg;
+            while (queue_try_remove(&g_display_queue, &next_msg)) {
                  printf("[Core 1] Skipping intermediate update\n");
                  free(msg); // Free the stale message
-                 msg_addr = multicore_fifo_pop_blocking();
+                 msg = next_msg;
-                 msg = (DisplayMessage *)msg_addr;
             }
             
             printf("[Core 1] Updating display with %d entries\n", msg->entries.count);
@@ -173,12 +189,16 @@ static void core1_display_init() {
 }
 
 void epaper_start_background_thread() {
+    // Initialize the queue before starting the thread
+    queue_init(&g_display_queue, sizeof(DisplayMessage*), QUEUE_LENGTH);
+
     printf("Launching e-Paper display init on core 1...\n");
     multicore_launch_core1(core1_display_init);
 }
 
 void epaper_send_update(const char *entry, bool finish_line) {
     if (!g_display_ready) return;  // Don't send if display isn't ready
+    // printf("[Core 0] Preparing display update: '%s' (finish_line=%d)\n", entry, finish_line);
     
     // Check if list is at capacity
     if (g_entry_list.count >= MAX_ENTRIES) {
@@ -224,11 +244,11 @@ void epaper_send_update(const char *entry, bool finish_line) {
         msg->yend = msg->ystart + 25;
     }
     
-    // Send message pointer to core 1 if FIFO has space
+    // Send message pointer to core 1 via Queue
-    if (multicore_fifo_wready()) {
+    if (queue_try_add(&g_display_queue, &msg)) {
-        multicore_fifo_push_blocking((uint32_t)msg);
+        // printf("[Core 0] Display update sent to core 1\n");
     } else {
-        printf("[Core 0] FIFO full, skipping display update\n");
+        printf("[Core 0] Queue full, skipping display update\n");
         free(msg);
     }
     

hello_usb.cpp

@@ -58,7 +58,7 @@ static bool execute_command(CommandAction action, const char* input) {
             if (parsed < 2) {
                 printf("Usage: /connect <ssid> <password>\n");
                 if (g_display_manager) g_display_manager->refresh("Usage: /connect <ssid> <pass>", nullptr);
-                // epaper_send_update("Usage: /connect <ssid> <pass>", true);
+                epaper_send_update("Usage: /connect <ssid> <pass>", true);
                 return true;
             }
             
@@ -67,11 +67,18 @@ static bool execute_command(CommandAction action, const char* input) {
             
             if (wifi_connect(ssid, password)) {
                 if (g_display_manager) g_display_manager->refresh("Connected!", ssid);
-                // epaper_send_update("Connected!", true);
+                int rc = wifi_save_credentials(ssid, password);
-                // wifi_save_credentials(ssid, password);
+                if (rc != 0) {
+                    char err_msg[32];
+                    snprintf(err_msg, sizeof(err_msg), "Flash Error: %d", rc);
+                    if (g_display_manager) g_display_manager->refresh(err_msg, nullptr);
+                    epaper_send_update(err_msg, true);
+                } else {
+                    epaper_send_update("Connected!", true);
+                }
             } else {
                 if (g_display_manager) g_display_manager->refresh("Connection Failed", nullptr);
-                // epaper_send_update("Connection Failed", true);
+                epaper_send_update("Connection Failed", true);
             }
             return true;
         }
@@ -219,20 +226,13 @@ int main() {
     sleep_ms(3000); // Give time for power to settle and serial to connect
     printf("System Booting...\n");
     
-    // Launch display initialization on core 1
+    // Launch display initialization on core 1, WIFI and Flash safe execute
     epaper_start_background_thread();
     
     DisplayManager display;
     display.init();
     g_display_manager = &display;
     
-    if (wifi_try_auto_connect()) {
-        display.refresh("WiFi Auto-Connected", nullptr);
-        epaper_send_update("WiFi Auto-Connected", true);
-    } else {
-        display.refresh("Waiting for Keyboard", nullptr);
-    }
-    
     printf("Initializing TinyUSB Host...\n");
     tuh_init(BOARD_TUH_RHPORT);
     printf("TinyUSB Host Initialized.\n");

wifi_manager.cpp

@@ -1,5 +1,7 @@
 #include "wifi_manager.h"
 #include "pico/cyw43_arch.h"
+#include "pico/multicore.h"
+#include "pico/flash.h"
 #include "hardware/flash.h"
 #include "hardware/sync.h"
 #include <stdio.h>
@@ -60,7 +62,20 @@ void wifi_scan() {
     }
 }
 
-void wifi_save_credentials(const char* ssid, const char* password) {
+// Helper struct for flash operations
+struct FlashWriteParams {
+    const uint8_t* data;
+    size_t size;
+};
+
+// Actual flash operation to be executed safely
+static void do_flash_write(void *param) {
+    FlashWriteParams *p = (FlashWriteParams*)param;
+    flash_range_erase(FLASH_TARGET_OFFSET, FLASH_SECTOR_SIZE);
+    flash_range_program(FLASH_TARGET_OFFSET, p->data, p->size);
+}
+
+int wifi_save_credentials(const char* ssid, const char* password) {
     WifiCreds creds;
     creds.magic = WIFI_CREDS_MAGIC;
     strncpy(creds.ssid, ssid, sizeof(creds.ssid) - 1);
@@ -68,17 +83,25 @@ void wifi_save_credentials(const char* ssid, const char* password) {
     strncpy(creds.password, password, sizeof(creds.password) - 1);
     creds.password[sizeof(creds.password) - 1] = '\0';
 
-    uint32_t ints = save_and_disable_interrupts();
+    FlashWriteParams params = { (const uint8_t*)&creds, sizeof(creds) };
-    flash_range_erase(FLASH_TARGET_OFFSET, FLASH_SECTOR_SIZE);
+    int rc = flash_safe_execute(do_flash_write, &params, 1000);
-    flash_range_program(FLASH_TARGET_OFFSET, (const uint8_t*)&creds, sizeof(creds));
-    restore_interrupts(ints);
     
+    if (rc == PICO_OK) {
         printf("WiFi credentials saved to flash.\n");
+    } else {
+        printf("Failed to save WiFi credentials: %d\n", rc);
+    }
+    return rc;
 }
 
 bool wifi_try_auto_connect() {
+    // On RP2040/RP2350, flash is memory-mapped at XIP_BASE (0x10000000).
+    // We can read from it directly like a normal pointer without special API calls.
+    // The hardware XIP controller handles fetching data from the flash chip.
     const WifiCreds* creds = (const WifiCreds*)(XIP_BASE + FLASH_TARGET_OFFSET);
     
+    // Check for the magic number to verify valid data exists.
+    // Erased flash reads as 0xFFFFFFFF, so this check fails if no data was saved.
     if (creds->magic != WIFI_CREDS_MAGIC) {
         printf("No saved WiFi credentials found.\n");
         return false;

wifi_manager.h

@@ -22,8 +22,9 @@ bool wifi_connect(const char* ssid, const char* password);
 
 /**
  * Saves the WiFi credentials to flash memory for auto-connect.
+ * Returns 0 (PICO_OK) on success, or an error code on failure.
  */
-void wifi_save_credentials(const char* ssid, const char* password);
+int wifi_save_credentials(const char* ssid, const char* password);
 
 /**
  * Attempts to connect using saved credentials.