diff --git a/Tools/AP_Periph/AP_Periph.cpp b/Tools/AP_Periph/AP_Periph.cpp
index 4d5cfdcbea155..85672d9d62f63 100644
--- a/Tools/AP_Periph/AP_Periph.cpp
+++ b/Tools/AP_Periph/AP_Periph.cpp
@@ -140,6 +140,10 @@ void AP_Periph_FW::init()
     node_stats.init();
 #endif
 
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+    serial_options.init();
+#endif
+
 #ifdef HAL_PERIPH_ENABLE_GPS
     if (gps.get_type(0) != AP_GPS::GPS_Type::GPS_TYPE_NONE && g.gps_port >= 0) {
         serial_manager.set_protocol_and_baud(g.gps_port, AP_SerialManager::SerialProtocol_GPS, AP_SERIALMANAGER_GPS_BAUD);
diff --git a/Tools/AP_Periph/AP_Periph.h b/Tools/AP_Periph/AP_Periph.h
index 26468de8c1e6a..97c89cdd3b5b2 100644
--- a/Tools/AP_Periph/AP_Periph.h
+++ b/Tools/AP_Periph/AP_Periph.h
@@ -36,6 +36,7 @@
 #include "rc_in.h"
 #include "batt_balance.h"
 #include "networking.h"
+#include "serial_options.h"
 
 #include <AP_NMEA_Output/AP_NMEA_Output.h>
 #if HAL_NMEA_OUTPUT_ENABLED && !(HAL_GCS_ENABLED && defined(HAL_PERIPH_ENABLE_GPS))
@@ -331,6 +332,10 @@ class AP_Periph_FW {
     void batt_balance_update();
     BattBalance battery_balance;
 #endif
+
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+    SerialOptions serial_options;
+#endif
     
 #if AP_TEMPERATURE_SENSOR_ENABLED
     AP_TemperatureSensor temperature_sensor;
diff --git a/Tools/AP_Periph/Parameters.cpp b/Tools/AP_Periph/Parameters.cpp
index 27c985a3bf621..2faf850167d59 100644
--- a/Tools/AP_Periph/Parameters.cpp
+++ b/Tools/AP_Periph/Parameters.cpp
@@ -610,6 +610,12 @@ const AP_Param::Info AP_Periph_FW::var_info[] = {
     GOBJECT(battery_balance, "BAL",  BattBalance),
 #endif
 
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+    // @Group: UART
+    // @Path: serial_options.cpp
+    GOBJECT(serial_options, "UART",  SerialOptions),
+#endif
+    
     // NOTE: sim parameters should go last
 #if AP_SIM_ENABLED
     // @Group: SIM_
diff --git a/Tools/AP_Periph/Parameters.h b/Tools/AP_Periph/Parameters.h
index ff64f16d1e950..9ff079217a22e 100644
--- a/Tools/AP_Periph/Parameters.h
+++ b/Tools/AP_Periph/Parameters.h
@@ -88,6 +88,7 @@ class Parameters {
         k_param_can_terminate0,
         k_param_can_terminate1,
         k_param_can_terminate2,
+        k_param_serial_options,
     };
 
     AP_Int16 format_version;
diff --git a/Tools/AP_Periph/serial_options.cpp b/Tools/AP_Periph/serial_options.cpp
new file mode 100644
index 0000000000000..cc480eee5b7f7
--- /dev/null
+++ b/Tools/AP_Periph/serial_options.cpp
@@ -0,0 +1,110 @@
+/*
+   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 <http://www.gnu.org/licenses/>.
+ */
+/*
+  serial options support, for serial over DroneCAN
+ */
+
+#include "AP_Periph.h"
+
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+
+#include "serial_options.h"
+#include <AP_SerialManager/AP_SerialManager_config.h>
+
+extern const AP_HAL::HAL &hal;
+
+const AP_Param::GroupInfo SerialOptions::var_info[] {
+
+#if HAL_HAVE_SERIAL0
+    // @Group: 0_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[0], "0_",  1, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL1
+    // @Group: 1_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[1], "1_",  2, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL2
+    // @Group: 2_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[2], "2_",  3, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL3
+    // @Group: 3_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[3], "3_",  4, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL4
+    // @Group: 4_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[4], "4_",  5, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL5
+    // @Group: 5_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[5], "5_",  6, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL6
+    // @Group: 6_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[6], "6_",  7, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL7
+    // @Group: 7_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[7], "7_",  8, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL8
+    // @Group: 8_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[8], "8_",  9, SerialOptions, SerialOptionsDev),
+#endif
+
+#if HAL_HAVE_SERIAL9
+    // @Group: 9_
+    // @Path: serial_options_dev.cpp
+    AP_SUBGROUPINFO(devs[9], "9_",  10, SerialOptions, SerialOptionsDev),
+#endif
+        
+    AP_GROUPEND
+};
+
+SerialOptions::SerialOptions(void)
+{
+    AP_Param::setup_object_defaults(this, var_info);
+}
+
+void SerialOptions::init(void)
+{
+    for (uint8_t i=0; i<ARRAY_SIZE(devs); i++) {
+        auto *uart = hal.serial(i);
+        if (uart != nullptr) {
+            auto &d = devs[i];
+            uart->set_options(d.options);
+            uart->set_flow_control(AP_HAL::UARTDriver::flow_control(d.rtscts.get()));
+        }
+    }
+}
+
+#endif  // HAL_PERIPH_ENABLE_SERIAL_OPTIONS
diff --git a/Tools/AP_Periph/serial_options.h b/Tools/AP_Periph/serial_options.h
new file mode 100644
index 0000000000000..d71bdf4313811
--- /dev/null
+++ b/Tools/AP_Periph/serial_options.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+
+#ifndef HAL_UART_NUM_SERIAL_PORTS
+#define HAL_UART_NUM_SERIAL_PORTS AP_HAL::HAL::num_serial
+#endif
+
+class SerialOptionsDev {
+public:
+    SerialOptionsDev(void);
+    static const struct AP_Param::GroupInfo var_info[];
+    AP_Int32 options;
+    AP_Int8 rtscts;
+};
+
+class SerialOptions {
+public:
+    friend class AP_Periph_FW;
+    SerialOptions(void);
+    void init(void);
+
+    static const struct AP_Param::GroupInfo var_info[];
+
+private:
+    SerialOptionsDev devs[HAL_UART_NUM_SERIAL_PORTS];
+};
+
+
+#endif // HAL_PERIPH_ENABLE_SERIAL_OPTIONS
diff --git a/Tools/AP_Periph/serial_options_dev.cpp b/Tools/AP_Periph/serial_options_dev.cpp
new file mode 100644
index 0000000000000..26ba2bb137453
--- /dev/null
+++ b/Tools/AP_Periph/serial_options_dev.cpp
@@ -0,0 +1,47 @@
+/*
+   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 <http://www.gnu.org/licenses/>.
+ */
+/*
+  serial options support, for serial over DroneCAN
+ */
+
+#include "AP_Periph.h"
+
+#ifdef HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+
+#include "serial_options.h"
+
+SerialOptionsDev::SerialOptionsDev(void)
+{
+    AP_Param::setup_object_defaults(this, var_info);
+}
+
+const AP_Param::GroupInfo SerialOptionsDev::var_info[] {
+
+    // @Param: OPTIONS
+    // @DisplayName: Serial options
+    // @Description: Control over UART options. The InvertRX option controls invert of the receive pin. The InvertTX option controls invert of the transmit pin. The HalfDuplex option controls half-duplex (onewire) mode, where both transmit and receive is done on the transmit wire. The Swap option allows the RX and TX pins to be swapped on STM32F7 based boards.
+    // @Bitmask: 0:InvertRX, 1:InvertTX, 2:HalfDuplex, 3:SwapTXRX, 4: RX_PullDown, 5: RX_PullUp, 6: TX_PullDown, 7: TX_PullUp, 8: RX_NoDMA, 9: TX_NoDMA, 10: Don't forward mavlink to/from, 11: DisableFIFO, 12: Ignore Streamrate
+    AP_GROUPINFO("OPTIONS", 1, SerialOptionsDev, options, 0),
+
+    // @Param: RTSCTS
+    // @DisplayName: Serial1 flow control
+    // @Description: Enable flow control. You must have the RTS and CTS pins available on the port. If this is set to 2 then flow control will be auto-detected by checking for the output buffer filling on startup.
+    // @Values: 0:Disabled,1:Enabled,2:Auto
+    AP_GROUPINFO("RTSCTS",  2, SerialOptionsDev, rtscts, float(AP_HAL::UARTDriver::FLOW_CONTROL_DISABLE)),
+
+    AP_GROUPEND
+};
+
+#endif  // HAL_PERIPH_ENABLE_SERIAL_OPTIONS
diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index d785c6161b82d..2c9432d85eb65 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -849,6 +849,7 @@ def configure_env(self, cfg, env):
             HAL_PERIPH_ENABLE_RPM = 1,
             HAL_PERIPH_ENABLE_RC_OUT = 1,
             HAL_PERIPH_ENABLE_ADSB = 1,
+            HAL_PERIPH_ENABLE_SERIAL_OPTIONS = 1,
             AP_ICENGINE_ENABLED = 0,
             AP_AIRSPEED_ENABLED = 1,
             AP_AIRSPEED_AUTOCAL_ENABLE = 0,
diff --git a/Tools/bootloaders/MatekL431-Serial_bl.bin b/Tools/bootloaders/MatekL431-Serial_bl.bin
new file mode 100755
index 0000000000000..80b78370907fa
Binary files /dev/null and b/Tools/bootloaders/MatekL431-Serial_bl.bin differ
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef-bl.dat b/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef-bl.dat
new file mode 100644
index 0000000000000..b9005f84941a6
--- /dev/null
+++ b/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef-bl.dat
@@ -0,0 +1,2 @@
+include ../MatekL431/hwdef-bl.inc
+
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef.dat
new file mode 100644
index 0000000000000..e9ace8923ddcb
--- /dev/null
+++ b/libraries/AP_HAL_ChibiOS/hwdef/MatekL431-Serial/hwdef.dat
@@ -0,0 +1,19 @@
+include ../MatekL431/hwdef.inc
+
+define HAL_PERIPH_ENABLE_SERIAL_OPTIONS
+
+# enable serial3 port with DMA
+undef PB10
+undef PB11
+PB10  USART3_TX USART3 SPEED_HIGH
+PB11  USART3_RX USART3 SPEED_HIGH
+
+# larger CAN pool for faster serial
+undef HAL_CAN_POOL_SIZE
+define HAL_CAN_POOL_SIZE 12000
+
+define HAL_USE_ADC FALSE
+
+# make the UARTn numbers in parameters match the silkscreen
+undef SERIAL_ORDER
+SERIAL_ORDER EMPTY USART1 USART2 USART3
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
index 3a0a8c372330d..e0b0f894a666a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
@@ -335,7 +335,7 @@
 #endif
 
 #ifndef AP_UART_MONITOR_ENABLED
-#define AP_UART_MONITOR_ENABLED defined(HAL_PERIPH_ENABLE_GPS) && (GPS_MOVING_BASELINE || BOARD_FLASH_SIZE>=256)
+#define AP_UART_MONITOR_ENABLED defined(HAL_PERIPH_ENABLE_SERIAL_OPTIONS) || (defined(HAL_PERIPH_ENABLE_GPS) && (GPS_MOVING_BASELINE || BOARD_FLASH_SIZE>=256))
 #endif
 
 #ifndef HAL_BOARD_LOG_DIRECTORY
diff --git a/libraries/AP_SerialManager/AP_SerialManager.cpp b/libraries/AP_SerialManager/AP_SerialManager.cpp
index 5b961da0722ea..24a694e2d074b 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.cpp
+++ b/libraries/AP_SerialManager/AP_SerialManager.cpp
@@ -28,37 +28,6 @@
 #include "AP_SerialManager.h"
 #include <GCS_MAVLink/GCS.h>
 
-#ifndef HAL_HAVE_SERIAL0
-#define HAL_HAVE_SERIAL0 HAL_NUM_SERIAL_PORTS > 0
-#endif
-#ifndef HAL_HAVE_SERIAL1
-#define HAL_HAVE_SERIAL1 HAL_NUM_SERIAL_PORTS > 1
-#endif
-#ifndef HAL_HAVE_SERIAL2
-#define HAL_HAVE_SERIAL2 HAL_NUM_SERIAL_PORTS > 2
-#endif
-#ifndef HAL_HAVE_SERIAL3
-#define HAL_HAVE_SERIAL3 HAL_NUM_SERIAL_PORTS > 3
-#endif
-#ifndef HAL_HAVE_SERIAL4
-#define HAL_HAVE_SERIAL4 HAL_NUM_SERIAL_PORTS > 4
-#endif
-#ifndef HAL_HAVE_SERIAL5
-#define HAL_HAVE_SERIAL5 HAL_NUM_SERIAL_PORTS > 5
-#endif
-#ifndef HAL_HAVE_SERIAL6
-#define HAL_HAVE_SERIAL6 HAL_NUM_SERIAL_PORTS > 6
-#endif
-#ifndef HAL_HAVE_SERIAL7
-#define HAL_HAVE_SERIAL7 HAL_NUM_SERIAL_PORTS > 7
-#endif
-#ifndef HAL_HAVE_SERIAL8
-#define HAL_HAVE_SERIAL8 HAL_NUM_SERIAL_PORTS > 8
-#endif
-#ifndef HAL_HAVE_SERIAL9
-#define HAL_HAVE_SERIAL9 HAL_NUM_SERIAL_PORTS > 9
-#endif
-
 extern const AP_HAL::HAL& hal;
 
 #ifndef DEFAULT_SERIAL0_PROTOCOL
diff --git a/libraries/AP_SerialManager/AP_SerialManager_config.h b/libraries/AP_SerialManager/AP_SerialManager_config.h
index 386d15dbfbc4e..88bf3ccaa3c7d 100644
--- a/libraries/AP_SerialManager/AP_SerialManager_config.h
+++ b/libraries/AP_SerialManager/AP_SerialManager_config.h
@@ -136,3 +136,34 @@
 #define AP_SERIALMANAGER_IMUOUT_BAUD           921600
 #define AP_SERIALMANAGER_IMUOUT_BUFSIZE_RX     128
 #define AP_SERIALMANAGER_IMUOUT_BUFSIZE_TX     2048
+
+#ifndef HAL_HAVE_SERIAL0
+#define HAL_HAVE_SERIAL0 HAL_NUM_SERIAL_PORTS > 0
+#endif
+#ifndef HAL_HAVE_SERIAL1
+#define HAL_HAVE_SERIAL1 HAL_NUM_SERIAL_PORTS > 1
+#endif
+#ifndef HAL_HAVE_SERIAL2
+#define HAL_HAVE_SERIAL2 HAL_NUM_SERIAL_PORTS > 2
+#endif
+#ifndef HAL_HAVE_SERIAL3
+#define HAL_HAVE_SERIAL3 HAL_NUM_SERIAL_PORTS > 3
+#endif
+#ifndef HAL_HAVE_SERIAL4
+#define HAL_HAVE_SERIAL4 HAL_NUM_SERIAL_PORTS > 4
+#endif
+#ifndef HAL_HAVE_SERIAL5
+#define HAL_HAVE_SERIAL5 HAL_NUM_SERIAL_PORTS > 5
+#endif
+#ifndef HAL_HAVE_SERIAL6
+#define HAL_HAVE_SERIAL6 HAL_NUM_SERIAL_PORTS > 6
+#endif
+#ifndef HAL_HAVE_SERIAL7
+#define HAL_HAVE_SERIAL7 HAL_NUM_SERIAL_PORTS > 7
+#endif
+#ifndef HAL_HAVE_SERIAL8
+#define HAL_HAVE_SERIAL8 HAL_NUM_SERIAL_PORTS > 8
+#endif
+#ifndef HAL_HAVE_SERIAL9
+#define HAL_HAVE_SERIAL9 HAL_NUM_SERIAL_PORTS > 9
+#endif