📌 SKR Mini V1.1 TMC UART Pins (#23970)

Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_V1_1.h

@@ -80,6 +80,23 @@
   #endif
 #endif
 
+#if HAS_TMC_UART                                  // Shared with EXP1
+  #define X_SERIAL_TX_PIN                  PC10
+  #define X_SERIAL_RX_PIN       X_SERIAL_TX_PIN
+
+  #define Y_SERIAL_TX_PIN                  PC11
+  #define Y_SERIAL_RX_PIN       Y_SERIAL_TX_PIN
+
+  #define Z_SERIAL_TX_PIN                  PC12
+  #define Z_SERIAL_RX_PIN       Z_SERIAL_TX_PIN
+
+  #define E0_SERIAL_TX_PIN                 PC14
+  #define E0_SERIAL_RX_PIN     E0_SERIAL_TX_PIN
+
+  // Reduce baud rate to improve software serial reliability
+  #define TMC_BAUD_RATE                   19200
+#endif
+
 //
 // Heaters / Fans
 //