2-ink display init and draws on second core

CMakeLists.txt

@@ -57,7 +57,7 @@ if (TARGET tinyusb_device)
     )
 
     # pull in common dependencies
-    target_link_libraries(hello_usb pico_stdlib pico_ssd1306 hardware_i2c Config ePaper GUI Fonts hardware_spi)
+    target_link_libraries(hello_usb pico_stdlib pico_ssd1306 hardware_i2c Config ePaper GUI Fonts hardware_spi pico_multicore)
 
     # enable usb output, disable uart output
     pico_enable_stdio_usb(hello_usb 1)

hello_usb.cpp

@@ -6,6 +6,7 @@
 
 #include "pico/stdlib.h"
 #include "pico/time.h" // Needed for time_us_64()
+#include "pico/multicore.h"
 #include <stdio.h>
 #include <ctype.h>
 #include <cstring>
@@ -28,6 +29,15 @@ static char g_last_echo[128] = "";
 static UBYTE *g_epd_image = NULL;  // Black image buffer
 static UBYTE *g_epd_red = NULL;    // Red image buffer
 
+// Synchronization flag for multicore initialization
+static volatile bool g_display_ready = false;
+
+// Display update message structure for inter-core communication
+typedef struct {
+    char line1[64];
+    char line2[64];
+} DisplayMessage;
+
 void init_epaper_display() {
     printf("Initializing 7.5\" e-Paper display (B V2)...\r\n");
     
@@ -111,6 +121,83 @@ void update_epaper_display(const char *line1, const char *line2) {
 // ASCII code for Backspace (often sent as 0x08)
 #define ASCII_BACKSPACE 8
 
+/**
+ * Send a display update message to core 1 via FIFO
+ */
+void send_display_update(const char *line1, const char *line2) {
+    if (!g_display_ready) return;  // Don't send if display isn't ready
+    
+    // Allocate message structure
+    DisplayMessage *msg = (DisplayMessage *)malloc(sizeof(DisplayMessage));
+    if (msg == NULL) {
+        printf("Failed to allocate display message!\n");
+        return;
+    }
+    
+    // Copy strings into message
+    strncpy(msg->line1, line1 ? line1 : "", sizeof(msg->line1) - 1);
+    msg->line1[sizeof(msg->line1) - 1] = '\0';
+    
+    strncpy(msg->line2, line2 ? line2 : "", sizeof(msg->line2) - 1);
+    msg->line2[sizeof(msg->line2) - 1] = '\0';
+    
+    // Send message pointer to core 1
+    multicore_fifo_push_blocking((uint32_t)msg);
+    
+    // Wait for core 1 to complete the update
+    // multicore_fifo_pop_blocking();
+}
+
+/**
+ * Core 1 function: Runs display initialization and update handling
+ */
+void core1_display_init() {
+    init_epaper_display();
+    g_display_ready = true;
+    
+    printf("[Core 1] Display ready, waiting for update messages...\n");
+    
+    // Core 1 main loop: handle display updates via FIFO
+    while (true) {
+        // Check if there's a message from core 0
+        if (multicore_fifo_rvalid()) {
+            // Read the message pointer
+            uint32_t msg_addr = multicore_fifo_pop_blocking();
+            DisplayMessage *msg = (DisplayMessage *)msg_addr;
+            
+            printf("[Core 1] Updating display: '%s' / '%s'\n", msg->line1, msg->line2);
+            
+            // Update the e-Paper display
+            if (g_epd_image != NULL && g_epd_red != NULL) {
+                UWORD imagesize = (EPD_7IN5B_V2_WIDTH / 8) * EPD_7IN5B_V2_HEIGHT;
+                for (UWORD i = 0; i < imagesize; i++) {
+                    g_epd_red[i] = 0xFF;
+                }
+                
+                // Paint_SelectImage(g_epd_image);
+                // Paint_Clear(WHITE);
+                
+                if (msg->line1[0] != '\0') {
+                    Paint_DrawString_EN(50, 100, msg->line1, &Font16, BLACK, WHITE);
+                }
+                if (msg->line2[0] != '\0') {
+                    Paint_DrawString_EN(50, 150, msg->line2, &Font16, BLACK, WHITE);
+                }
+                
+                EPD_7IN5B_V2_Display(g_epd_image, g_epd_red);
+            }
+            
+            // Free the message (it was allocated by core 0)
+            free(msg);
+            
+            // Signal back to core 0 that update is complete
+            multicore_fifo_push_blocking(1);
+        }
+        
+        sleep_ms(10);
+    }
+}
+
 void wait_for_usb_connection(DisplayManager &display) {
     printf("Waiting for USB host to connect...\n");
     while (!stdio_usb_connected()) {
@@ -118,9 +205,6 @@ void wait_for_usb_connection(DisplayManager &display) {
     }
     printf("\nConnection Established! Starting Echo Session...\n");
     display.refresh(">", nullptr);
-    
-    // Initialize e-Paper display
-    init_epaper_display();
 }
 
 void run_echo_session(DisplayManager &display) {
@@ -140,9 +224,10 @@ void run_echo_session(DisplayManager &display) {
                 if (buffer_index > 0) {
                     buffer_index--;
                     printf("\b \b");
-                    // update display to reflect removed char
+                    // update displays to reflect removed char
                     input_buffer[buffer_index] = '\0';
                     display.refresh(input_buffer, g_last_echo);
+                    // send_display_update(input_buffer, g_last_echo);
                 }
             } else if (input_char == '\r' || input_char == '\n') {
                 echo_and_reset(input_buffer, &buffer_index);
@@ -152,16 +237,18 @@ void run_echo_session(DisplayManager &display) {
                     g_last_echo[i] = input_buffer[i];
                 }
                 g_last_echo[i] = '\0';
-                // Update OLED to show cleared input and last echo
+                // Update both displays to show cleared input and last echo
                 display.set_last_echo(g_last_echo);
                 display.refresh("", g_last_echo);
+                send_display_update("", g_last_echo);
             } else if (buffer_index < (MAX_INPUT_LEN - 1) && isprint(input_char)) {
                 printf("%c", input_char);
                 input_buffer[buffer_index] = input_char;
                 buffer_index++;
-                // update OLED with current input
+                // update both displays with current input
                 input_buffer[buffer_index] = '\0';
                 display.refresh(input_buffer, g_last_echo);
+                // send_display_update(input_buffer, g_last_echo);
             }
         }
         sleep_us(100);
@@ -172,7 +259,9 @@ void run_echo_session(DisplayManager &display) {
 
 int main() {
     stdio_init_all();
-
+    // Launch display initialization on core 1
+    printf("Launching e-Paper display init on core 1...\n");
+    multicore_launch_core1(core1_display_init);
     
     DisplayManager display;
     display.init();