FYSETC E4 board support (#20032)

Marlin/src/core/boards.h

 #define BOARD_MRR_ESPA                6001  // MRR ESPA board based on ESP32 (native pins only)
 #define BOARD_MRR_ESPE                6002  // MRR ESPE board based on ESP32 (with I2S stepper stream)
 #define BOARD_E4D_BOX                 6003  // E4d@BOX
+#define BOARD_FYSETC_E4               6004  // FYSETC E4
 
 //
 // SAMD51 ARM Cortex M4

Marlin/src/pins/esp32/pins_FYSETC_E4.h

+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+/**
+ * FYSETC E4 pin assignments
+ * FYSETC E4 is a 3D printer control board based on the ESP32 microcontroller.
+ * Supports 4 stepper drivers, heated bed, single hotend.
+ */
+
+#ifndef ARDUINO_ARCH_ESP32
+  #error "Oops! Select an ESP32 board in 'Tools > Board.'"
+#elif EXTRUDERS > 1 || E_STEPPERS > 1
+  #error "FYSETC E4 only supports one E Stepper. Comment out this line to continue."
+#elif HOTENDS > 1
+  #error "FYSETC E4 currently supports only one hotend. Comment out this line to continue."
+#endif
+
+#define BOARD_INFO_NAME       "FYSETC_E4"
+#define DEFAULT_MACHINE_NAME  BOARD_INFO_NAME
+
+//
+// Disable I2S stepper stream
+//
+#undef I2S_STEPPER_STREAM
+#define I2S_WS                                -1
+#define I2S_BCK                               -1
+#define I2S_DATA                              -1
+
+//
+// Limit Switches
+//
+#define X_STOP_PIN                            34
+#define Y_STOP_PIN                            35
+#define Z_STOP_PIN                            15
+
+//
+// Steppers
+//
+#define X_STEP_PIN                            27
+#define X_DIR_PIN                             26
+#define X_ENABLE_PIN                          25
+
+#define Y_STEP_PIN                            33
+#define Y_DIR_PIN                             32
+#define Y_ENABLE_PIN                X_ENABLE_PIN
+
+#define Z_STEP_PIN                            14
+#define Z_DIR_PIN                             12
+#define Z_ENABLE_PIN                X_ENABLE_PIN
+
+#define E0_STEP_PIN                           16
+#define E0_DIR_PIN                            17
+#define E0_ENABLE_PIN               X_ENABLE_PIN
+
+#if HAS_TMC_UART
+  //
+  // TMC2209 stepper drivers
+  //
+
+  //
+  // Hardware serial 1
+  //
+  #define X_HARDWARE_SERIAL              Serial1
+  #define Y_HARDWARE_SERIAL              Serial1
+  #define Z_HARDWARE_SERIAL              Serial1
+  #define E0_HARDWARE_SERIAL             Serial1
+
+  #define TMC_BAUD_RATE 115200
+#endif
+
+//
+// Temperature Sensors
+//
+#define TEMP_0_PIN                            36  // Analog Input
+#define TEMP_BED_PIN                          39  // Analog Input
+
+//
+// Heaters / Fans
+//
+#define HEATER_0_PIN                           2
+#define FAN_PIN                               13
+#define HEATER_BED_PIN                         4
+
+//
+// MicroSD card
+//
+#define MOSI_PIN                              23
+#define MISO_PIN                              19
+#define SCK_PIN                               18
+#define SDSS                                   5
+#define USES_SHARED_SPI                           // SPI is shared by SD card with TMC SPI drivers
+
+/**
+ * Hardware serial pins
+ *
+ * Override these pins in Configuration.h or Configuration_adv.h if needed.
+ *
+ * Note: Serial2 can be defined using HARDWARE_SERIAL2_RX and HARDWARE_SERIAL2_TX
+ *       but MRR ESPA does not have enough spare pins for such reassignment.
+ */
+#ifndef HARDWARE_SERIAL1_RX
+  #define HARDWARE_SERIAL1_RX                 21
+#endif
+#ifndef HARDWARE_SERIAL1_TX
+  #define HARDWARE_SERIAL1_TX                 22
+#endif

Marlin/src/pins/pins.h

   #include "esp32/pins_MRR_ESPE.h"              // ESP32                                  env:esp32
 #elif MB(E4D_BOX)
   #include "esp32/pins_E4D.h"                   // ESP32                                  env:esp32
+#elif MB(FYSETC_E4)
+  #include "esp32/pins_FYSETC_E4.h"             // ESP32                                  env:FYSETC_E4
 
 //
 // Adafruit Grand Central M4 (SAMD51 ARM Cortex-M4)

platformio.ini

 #upload_port   = marlinesp.local
 #board_build.flash_mode = qio
 
+[env:FYSETC_E4]
+platform               = espressif32@1.11.2
+extends                = env:esp32
+board_build.partitions = default_16MB.csv
+
 #
 # Teensy 3.1 / 3.2 (ARM Cortex-M4)
 #