M485 command for RS485 support in Marlin

Marlin/Configuration.h

@@ -112,6 +112,16 @@
 //#define SERIAL_PORT_3 1
 //#define BAUDRATE_3 250000   // :[2400, 9600, 19200, 38400, 57600, 115200, 250000, 500000, 1000000] Enable to override BAUDRATE
 
+/**
+ * Select a serial port to communicate with RS485 protocol
+ * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
+ */
+//#define RS485_SERIAL_PORT 1
+#ifdef RS485_SERIAL_PORT
+  //#define M485_PROTOCOL 1   // Check your host for protocol compatibility
+  //#define RS485_BUS_BUFFER_SIZE 128
+#endif
+
 // Enable the Bluetooth serial interface on AT90USB devices
 //#define BLUETOOTH
 

Marlin/src/HAL/STM32/HAL.h

@@ -117,6 +117,14 @@
   #endif
 #endif
 
+#ifdef RS485_SERIAL_PORT
+  #if WITHIN(RS485_SERIAL_PORT, 1, 9)
+    #define RS485_SERIAL MSERIAL(RS485_SERIAL_PORT)
+  #else
+    #error "RS485_SERIAL_PORT must be from 1 to 9."
+  #endif
+#endif
+
 /**
  * TODO: review this to return 1 for pins that are not analog input
  */

Marlin/src/HAL/STM32F1/HAL.h

@@ -143,6 +143,17 @@
   #endif
 #endif
 
+#ifdef RS485_SERIAL_PORT
+  #if RS485_SERIAL_PORT == -1
+    #define RS485_SERIAL UsbSerial
+  #elif WITHIN(RS485_SERIAL_PORT, 1, NUM_UARTS)
+    #define RS485_SERIAL MSERIAL(RS485_SERIAL_PORT)
+  #else
+    #define RS485_SERIAL MSERIAL(1) // dummy port
+    static_assert(false, "RS485_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ".")
+  #endif
+#endif
+
 /**
  * TODO: review this to return 1 for pins that are not analog input
  */

Marlin/src/MarlinCore.cpp

@@ -261,6 +261,10 @@
   #include "tests/marlin_tests.h"
 #endif
 
+#if HAS_RS485_SERIAL
+  #include "feature/rs485.h"
+#endif
+
 PGMSTR(M112_KILL_STR, "M112 Shutdown");
 
 MarlinState marlin_state = MarlinState::MF_INITIALIZING;
@@ -1642,6 +1646,10 @@ void setup() {
     SETUP_RUN(bdl.init(I2C_BD_SDA_PIN, I2C_BD_SCL_PIN, I2C_BD_DELAY));
   #endif
 
+  #if HAS_RS485_SERIAL
+    SETUP_RUN(rs485_init());
+  #endif
+
   #if ENABLED(FT_MOTION)
     SETUP_RUN(ftMotion.init());
   #endif

Marlin/src/feature/power.cpp

@@ -201,7 +201,7 @@ void Power::power_off() {
   /**
    * Check all conditions that would signal power needing to be on.
    *
-   * @returns bool  if power is needed
+   * @return bool  if power is needed
    */
   bool Power::is_power_needed() {
 

Marlin/src/feature/rs485.cpp

@@ -0,0 +1,39 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2024 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/>.
+ *
+ */
+#include "../inc/MarlinConfig.h"
+
+#if HAS_RS485_SERIAL
+
+#include "rs485.h"
+
+HardwareSerialBusIO rs485BusIO(&RS485_SERIAL);
+RS485Bus<RS485_BUS_BUFFER_SIZE> rs485Bus(rs485BusIO, RS485_RX_ENABLE_PIN, RS485_TX_ENABLE_PIN);
+
+PhotonProtocol rs485Protocol;
+
+Packetizer rs485Packetizer(rs485Bus, rs485Protocol);
+
+uint8_t rs485Buffer[RS485_SEND_BUFFER_SIZE];
+
+void rs485_init() { RS485_SERIAL.begin(57600); }
+
+#endif // HAS_RS485_SERIAL

Marlin/src/feature/rs485.h

@@ -0,0 +1,40 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2024 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
+
+#include "../inc/MarlinConfigPre.h"
+
+#include <rs485/rs485bus.hpp>
+#include <rs485/bus_adapters/hardware_serial.h>
+
+#include <rs485/protocols/photon.h>
+#include <rs485/packetizer.h>
+
+#define RS485_SEND_BUFFER_SIZE 32
+
+extern HardwareSerialBusIO rs485BusIO;
+extern RS485Bus<RS485_BUS_BUFFER_SIZE> rs485Bus;
+extern PhotonProtocol rs485Protocol;
+extern Packetizer rs485Packetizer;
+extern uint8_t rs485Buffer[RS485_SEND_BUFFER_SIZE];
+
+void rs485_init();

Marlin/src/gcode/feature/rs485/M485.cpp

@@ -0,0 +1,127 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2024 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/>.
+ *
+ */
+
+#include "../../../inc/MarlinConfig.h"
+
+#if HAS_RS485_SERIAL
+
+#include "../../../feature/rs485.h"
+#include "../../gcode.h"
+
+void write_packet_data() {
+
+  Packet packet = rs485Packetizer.getPacket();
+  for (size_t i = packet.startIndex; i <= packet.endIndex; i++) {
+    const uint8_t data = rs485Bus[i];
+    if (data < 0x10) SERIAL_ECHOPGM_P(PSTR("0"));
+    SERIAL_PRINT(data, PrintBase::Hex);
+  }
+
+  SERIAL_EOL();
+}
+
+static void rs485_write_failed(const PacketWriteResult writeResult) {
+  SERIAL_ERROR_START();
+  SERIAL_ECHOPGM("RS485: Write failed ");
+  switch (writeResult) {
+    case PacketWriteResult::FAILED_INTERRUPTED: SERIAL_ECHOPGM("interrupted"); break;
+    case PacketWriteResult::FAILED_BUFFER_FULL: SERIAL_ECHOPGM("buffer full"); break;
+    case PacketWriteResult::FAILED_TIMEOUT: SERIAL_ECHOPGM("timeout"); break;
+  }
+  SERIAL_EOL();
+}
+
+void GcodeSuite::M485() {
+  if (strlen(parser.string_arg) & 1) {
+    SERIAL_ERROR_MSG("String must contain an even number of bytes.");
+    return;
+  }
+
+  if (strlen(parser.string_arg) > RS485_SEND_BUFFER_SIZE * 2) {
+    SERIAL_ERROR_MSG("String too long (" STRINGIFY(RS485_SEND_BUFFER_SIZE) " bytes max).");
+    return;
+  }
+
+  // Convert the string to bytes in the buffer
+  for (size_t i = 0; i < strlen(parser.string_arg); i += 2) {
+    const uint8_t nybble1 = HEXCHR(parser.string_arg[i]),
+                  nybble2 = HEXCHR(parser.string_arg[i + 1]);
+
+    if (nybble1 == -1 || nybble2 == -1) {
+      SERIAL_ERROR_START();
+      SERIAL_ECHOPGM("Not a hex character: ");
+      SERIAL_CHAR(nybble1 == -1 ? parser.string_arg[i] : parser.string_arg[i+1]);
+      SERIAL_EOL();
+      return;
+    }
+
+    rs485Buffer[i >> 1] = (nybble1 & 0x0F) << 4 | (nybble2 & 0x0F);
+  }
+
+  rs485Packetizer.setMaxReadTimeout(50000);  // This can be super small since ideally any packets will already be in our buffer
+  rs485Packetizer.setFalsePacketVerificationTimeout(5000);
+
+  // Read and ignore any packets that may have come in, before we write.
+
+  while (rs485Packetizer.hasPacket()) {
+    #if M485_PROTOCOL >= 2
+      SERIAL_ECHO_START();
+    #endif
+    SERIAL_ECHO(F("rs485-"), F("unexpected-packet: "));
+    write_packet_data();
+    rs485Packetizer.clearPacket();
+  }
+
+  const PacketWriteResult writeResult = rs485Packetizer.writePacket(rs485Buffer, strlen(parser.string_arg) / 2);
+  switch (writeResult) {
+    default: rs485_write_failed(writeResult);
+    case PacketWriteResult::OK: break;  // Nothing to do
+  }
+
+  //millis_t startTime = millis();
+  bool hasPacket = rs485Packetizer.hasPacket();
+  //millis_t endTime = millis();
+  //#if M485_PROTOCOL >= 2
+  //  SERIAL_ECHO_START();
+  //#endif
+  //SERIAL_ECHOLN(F("rs485-"), F("time: "), endTime - startTime);
+
+  #if M485_PROTOCOL >= 2
+    SERIAL_ECHO_START();
+  #endif
+
+  SERIAL_ECHO(F("rs485-"));
+  if (!hasPacket) {
+    #if M485_PROTOCOL >= 2
+      SERIAL_ECHOLN(F("timeout"));
+    #else
+      SERIAL_ECHOLN(F("reply: TIMEOUT"));
+    #endif
+    return;
+  }
+
+  SERIAL_ECHO(F("reply: "));
+  write_packet_data();
+  rs485Packetizer.clearPacket();
+}
+
+#endif // HAS_RS485_SERIAL

Marlin/src/gcode/gcode.cpp

@@ -897,6 +897,10 @@ void GcodeSuite::process_parsed_command(const bool no_ok/*=false*/) {
         case 430: M430(); break;                                  // M430: Read the system current (A), voltage (V), and power (W)
       #endif
 
+      #if HAS_RS485_SERIAL
+        case 485: M485(); break;                                  // M485: Send RS485 packets
+      #endif
+
       #if ENABLED(CANCEL_OBJECTS)
         case 486: M486(); break;                                  // M486: Identify and cancel objects
       #endif

Marlin/src/gcode/gcode.h

@@ -243,6 +243,7 @@
  * M425 - Enable/Disable and tune backlash correction. (Requires BACKLASH_COMPENSATION and BACKLASH_GCODE)
  * M428 - Set the home_offset based on the current_position. Nearest edge applies. (Disabled by NO_WORKSPACE_OFFSETS or DELTA)
  * M430 - Read the system current, voltage, and power (Requires POWER_MONITOR_CURRENT, POWER_MONITOR_VOLTAGE, or POWER_MONITOR_FIXED_VOLTAGE)
+ * M485 - Send RS485 packets (Requires RS485_SERIAL_PORT)
  * M486 - Identify and cancel objects. (Requires CANCEL_OBJECTS)
  * M500 - Store parameters in EEPROM. (Requires EEPROM_SETTINGS)
  * M501 - Restore parameters from EEPROM. (Requires EEPROM_SETTINGS)
@@ -1063,6 +1064,10 @@ class GcodeSuite {
     static void M430();
   #endif
 
+  #if HAS_RS485_SERIAL
+    static void M485();
+  #endif
+
   #if ENABLED(CANCEL_OBJECTS)
     static void M486();
   #endif

Marlin/src/gcode/parser.cpp

@@ -274,9 +274,12 @@ void GCodeParser::parse(char *p) {
 
   // Only use string_arg for these M codes
   if (letter == 'M') switch (codenum) {
-    TERN_(GCODE_MACROS, case 810 ... 819:)
     TERN_(EXPECTED_PRINTER_CHECK, case 16:)
-    case 23: case 28: case 30: case 117 ... 118: case 928:
+    TERN_(SDSUPPORT, case 23: case 28: case 30: case 928:)
+    TERN_(HAS_STATUS_MESSAGE, case 117:)
+    TERN_(HAS_RS485_SERIAL, case 485:)
+    TERN_(GCODE_MACROS, case 810 ... 819:)
+    case 118:
       string_arg = unescape_string(p);
       return;
     default: break;

Marlin/src/inc/Conditionals_LCD.h

@@ -1669,6 +1669,9 @@
 #if SERIAL_PORT == -1 || SERIAL_PORT_2 == -1 || SERIAL_PORT_3 == -1
   #define HAS_USB_SERIAL 1
 #endif
+#ifdef RS485_SERIAL_PORT
+  #define HAS_RS485_SERIAL 1
+#endif
 #if SERIAL_PORT_2 == -2
   #define HAS_ETHERNET 1
 #endif

Marlin/src/inc/Conditionals_post.h

@@ -1827,11 +1827,12 @@
 //
 
 // Flag the indexed hardware serial ports in use
-#define SERIAL_IN_USE(N) (   (defined(SERIAL_PORT)      && N == SERIAL_PORT) \
-                          || (defined(SERIAL_PORT_2)    && N == SERIAL_PORT_2) \
-                          || (defined(SERIAL_PORT_3)    && N == SERIAL_PORT_3) \
-                          || (defined(MMU2_SERIAL_PORT) && N == MMU2_SERIAL_PORT) \
-                          || (defined(LCD_SERIAL_PORT)  && N == LCD_SERIAL_PORT) )
+#define SERIAL_IN_USE(N) (   (defined(SERIAL_PORT)       && N == SERIAL_PORT) \
+                          || (defined(SERIAL_PORT_2)     && N == SERIAL_PORT_2) \
+                          || (defined(SERIAL_PORT_3)     && N == SERIAL_PORT_3) \
+                          || (defined(MMU2_SERIAL_PORT)  && N == MMU2_SERIAL_PORT) \
+                          || (defined(LCD_SERIAL_PORT)   && N == LCD_SERIAL_PORT) \
+                          || (defined(RS485_SERIAL_PORT) && N == RS485_SERIAL_PORT) )
 
 // Flag the named hardware serial ports in use
 #define TMC_UART_IS(A,N) (defined(A##_HARDWARE_SERIAL) && (CAT(HW_,A##_HARDWARE_SERIAL) == HW_Serial##N || CAT(HW_,A##_HARDWARE_SERIAL) == HW_MSerial##N))

Marlin/src/inc/SanityCheck.h

@@ -2919,6 +2919,8 @@ static_assert(NUM_SERVOS <= NUM_SERVO_PLUGS, "NUM_SERVOS (or some servo index) i
     #error "MMU2_SERIAL_PORT cannot be the same as SERIAL_PORT_2."
   #elif defined(LCD_SERIAL_PORT) && MMU2_SERIAL_PORT == LCD_SERIAL_PORT
     #error "MMU2_SERIAL_PORT cannot be the same as LCD_SERIAL_PORT."
+  #elif defined(RS485_SERIAL_PORT) && MMU2_SERIAL_PORT == RS485_SERIAL_PORT
+    #error "MMU2_SERIAL_PORT cannot be the same as RS485_SERIAL_PORT."
   #endif
 #endif
 
@@ -2930,6 +2932,8 @@ static_assert(NUM_SERVOS <= NUM_SERVO_PLUGS, "NUM_SERVOS (or some servo index) i
     #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT."
   #elif defined(SERIAL_PORT_2) && LCD_SERIAL_PORT == SERIAL_PORT_2
     #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2."
+  #elif defined(RS485_SERIAL_PORT) && LCD_SERIAL_PORT == RS485_SERIAL_PORT
+    #error "LCD_SERIAL_PORT cannot be the same as RS485_SERIAL_PORT."
   #endif
 #else
   #if HAS_DGUS_LCD
@@ -2943,6 +2947,17 @@ static_assert(NUM_SERVOS <= NUM_SERVO_PLUGS, "NUM_SERVOS (or some servo index) i
   #endif
 #endif
 
+/**
+ * RS485 bus requires a dedicated serial port
+ */
+#ifdef RS485_SERIAL_PORT
+  #if RS485_SERIAL_PORT == SERIAL_PORT
+    #error "RS485_SERIAL_PORT cannot be the same as SERIAL_PORT."
+  #elif defined(SERIAL_PORT_2) && RS485_SERIAL_PORT == SERIAL_PORT_2
+    #error "RS485_SERIAL_PORT cannot be the same as SERIAL_PORT_2."
+  #endif
+#endif
+
 /**
  * Check existing CS pins against enabled TMC SPI drivers.
  */