fix: resolve byte-to-byte gap stretching in FCOB driver by introducing zero-gap double-buffered SPI transmission queue

App/main.c

@@ -164,13 +164,23 @@ void WS2812_Write24Bit(u8 g, u8 r, u8 b)
     SPCTL = 0xD0; // Enable SPI at SYSCLK/4 (6.0 MHz)
     SPSTAT = 0xC0; // Clear flags
     
-    for (i = 0; i < 15; i++)
+    SPDAT = buf[0]; // Goes to shift register immediately
+    // Wait at least 1 SPI clock cycle (8 system cycles) to avoid WCOL
+    _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_();
+    SPDAT = buf[1]; // Goes to transmit buffer
+    
+    for (i = 2; i < 15; i++)
     {
-        SPDAT = buf[i];
-        while (!(SPSTAT & 0x80));
+        while (!(SPSTAT & 0x80)); // Wait for buf[i-2] to finish, buf[i-1] moves to shifter
         SPSTAT = 0xC0;
+        SPDAT = buf[i];          // Write buf[i] to transmit buffer (zero gap!)
     }
     
+    while (!(SPSTAT & 0x80)); // Wait for buf[13] to finish, buf[14] moves to shifter
+    SPSTAT = 0xC0;
+    while (!(SPSTAT & 0x80)); // Wait for buf[14] to finish
+    SPSTAT = 0xC0;
+    
     SPCTL = 0x90; // Disable SPI
     WS2812_DI = 0;
     MOTOR = 0;   // Ensure motor is off