Lerdge-K TMC 2208/9 UART pins (#21299)

Marlin/src/pins/stm32f4/pins_LERDGE_K.h

@@ -96,6 +96,50 @@
 //  #define E1_CS_PIN                       PE4
 //#endif
 
+#if HAS_TMC_UART
+  /**
+   * TMC2208/TMC2209 stepper drivers
+   */
+  #ifndef X_SERIAL_TX_PIN
+    #define X_SERIAL_TX_PIN                 PB2
+  #endif
+  #ifndef X_SERIAL_RX_PIN
+    #define X_SERIAL_RX_PIN                 PB2
+  #endif
+  #ifndef Y_SERIAL_TX_PIN
+    #define Y_SERIAL_TX_PIN                 PE2
+  #endif
+  #ifndef Y_SERIAL_RX_PIN
+    #define Y_SERIAL_RX_PIN                 PE2
+  #endif
+  #ifndef Z_SERIAL_TX_PIN
+    #define Z_SERIAL_TX_PIN                 PE3
+  #endif
+  #ifndef Z_SERIAL_RX_PIN
+    #define Z_SERIAL_RX_PIN                 PE3
+  #endif
+  #ifndef E0_SERIAL_TX_PIN
+    #define E0_SERIAL_TX_PIN                PE4
+  #endif
+  #ifndef E0_SERIAL_RX_PIN
+    #define E0_SERIAL_RX_PIN                PE4
+  #endif
+  #ifndef E1_SERIAL_TX_PIN
+    #define E1_SERIAL_TX_PIN                PE1
+  #endif
+  #ifndef E1_SERIAL_RX_PIN
+    #define E1_SERIAL_RX_PIN                PE1
+  #endif
+  #ifndef EX_SERIAL_TX_PIN
+    #define E2_SERIAL_TX_PIN                PE0
+  #endif
+  #ifndef EX_SERIAL_RX_PIN
+    #define E2_SERIAL_RX_PIN                PE0
+  #endif
+  // Reduce baud rate to improve software serial reliability
+  #define TMC_BAUD_RATE                    19200
+#endif
+
 //
 // Temperature Sensors
 //