DMA Serial Reading to Circular buffer

Marlin/Configuration_adv.h

@@ -2649,10 +2649,12 @@
  //#define FULL_REPORT_TO_HOST_FEATURE // Auto-report the machine status like Grbl CNC
 #endif
 
-// Bad Serial-connections can miss a received command by sending an 'ok'
-// Therefore some clients abort after 30 seconds in a timeout.
-// Some other clients start sending commands while receiving a 'wait'.
-// This "wait" is only sent when the buffer is empty. 1 second is a good value here.
+/**
+ * Bad Serial-connections can miss a received command by sending an 'ok'
+ * Therefore some clients abort after 30 seconds in a timeout.
+ * Some other clients start sending commands while receiving a 'wait'.
+ * This "wait" is only sent when the buffer is empty. 1 second is a good value here.
+ */
 //#define NO_TIMEOUTS 1000 // (ms)
 
 // Some clients will have this feature soon. This could make the NO_TIMEOUTS unnecessary.
@@ -2665,6 +2667,15 @@
 // For serial echo, the number of digits after the decimal point
 //#define SERIAL_FLOAT_PRECISION 4
 
+/**
+ * This feature is EXPERIMENTAL so use with caution and test thoroughly.
+ * Enable this option to receive data on the serial ports via the onboard DMA
+ * controller for more stable and reliable high-speed serial communication.
+ * Only some STM32 MCUs are currently supported.
+ * Note: This has no effect on emulated USB serial ports.
+ */
+//#define SERIAL_DMA
+
 /**
  * Set the number of proportional font spaces required to fill up a typical character space.
  * This can help to better align the output of commands like `G29 O` Mesh Output.
@@ -3442,9 +3453,8 @@
 /**
  * TWI/I2C BUS
  *
- * This feature is an EXPERIMENTAL feature so it shall not be used on production
- * machines. Enabling this will allow you to send and receive I2C data from slave
- * devices on the bus.
+ * This feature is EXPERIMENTAL but may be useful for custom I2C peripherals.
+ * Enable this to send and receive I2C data from slave devices on the bus.
  *
  * ; Example #1
  * ; This macro send the string "Marlin" to the slave device with address 0x63 (99)

Marlin/src/HAL/AVR/MarlinSerial.h

@@ -37,10 +37,6 @@
 #include "../../core/types.h"
 #include "../../core/serial_hook.h"
 
-#ifndef SERIAL_PORT
- #define SERIAL_PORT 0
-#endif
-
 #ifndef USBCON
 
  // The presence of the UBRRH register is used to detect a UART.

Marlin/src/HAL/AVR/inc/Conditionals_LCD.h

@@ -20,3 +20,7 @@
  *
  */
 #pragma once
+
+#ifndef SERIAL_PORT
+ #define SERIAL_PORT 0
+#endif

Marlin/src/HAL/LPC1768/MarlinSerial.h

@@ -30,16 +30,6 @@
 #endif
 #include "../../core/serial_hook.h"
 
-#ifndef SERIAL_PORT
- #define SERIAL_PORT 0
-#endif
-#ifndef RX_BUFFER_SIZE
- #define RX_BUFFER_SIZE 128
-#endif
-#ifndef TX_BUFFER_SIZE
- #define TX_BUFFER_SIZE 32
-#endif
-
 class MarlinSerial : public HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE> {
 public:
  MarlinSerial(LPC_UART_TypeDef *UARTx) : HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE>(UARTx) { }

Marlin/src/HAL/LPC1768/inc/Conditionals_LCD.h

@@ -20,3 +20,7 @@
  *
  */
 #pragma once
+
+#ifndef SERIAL_PORT
+ #define SERIAL_PORT 0
+#endif

Marlin/src/HAL/LPC1768/inc/Conditionals_adv.h

@@ -24,3 +24,10 @@
 #if DISABLED(NO_SD_HOST_DRIVE)
  #define HAS_SD_HOST_DRIVE 1
 #endif
+
+#ifndef RX_BUFFER_SIZE
+ #define RX_BUFFER_SIZE 128
+#endif
+#ifndef TX_BUFFER_SIZE
+ #define TX_BUFFER_SIZE 32
+#endif