diff --git a/LocoNet.cpp b/LocoNet.cpp
index 13c6989..d1f732b 100644
--- a/LocoNet.cpp
+++ b/LocoNet.cpp
@@ -83,11 +83,13 @@ uint8_t eeprom_read_byte(const uint8_t* offset) {
 void eeprom_write_byte(const uint8_t* offset, uint8_t value) {
 	EEPROM.write((int)offset, value);
 }
-#elif defined(STM32F1)
+#elif defined(STM32F1) 
 #  include <FreeRTOS.h>
 #  include <task.h>
 #  include <libopencm3/stm32/gpio.h>
 #  include <cstdint>
+#elif defined(ARDUINO_ARCH_STM32)
+#  include <cstdint>
 #else
 #  include <avr/eeprom.h>
 #  include <avr/wdt.h>
@@ -154,7 +156,7 @@ void LocoNetClass::setTxPin(uint8_t txPin)
 	LnPortRegisterType bitMaskTest = 0x01;
 	LnPortRegisterType bitNum = 0;
 
-	LnPortRegisterType port = digitalPinToPort(txPin);
+	auto port = digitalPinToPort(txPin);
 	LnPortAddrType out = portOutputRegister(port);
 
 	while (bitMask != bitMaskTest)
@@ -618,7 +620,7 @@ void LocoNetThrottleClass::updateState(TH_STATE State, uint8_t ForceNotify)
 
 void LocoNetThrottleClass::updateStatus1(uint8_t Status, uint8_t ForceNotify)
 {
-	register uint8_t Mask;	// Temporary uint8_t Variable for bitwise AND to force
+	uint8_t Mask;	// Temporary uint8_t Variable for bitwise AND to force
 	// the compiler to only do 8 bit operations not 16
 
 	if (ForceNotify || myStatus1 != Status)
@@ -1428,7 +1430,7 @@ void LocoNetFastClockClass::process66msActions(void)
 	}
 }
 
-#if defined(STM32F1)
+#if defined(STM32F1) || defined(ARDUINO_ARCH_STM32)
 // STM31F1 has no EEPROM.
 #else
 
@@ -1760,7 +1762,7 @@ SV_STATUS LocoNetSystemVariableClass::doDeferredProcessing(void)
 	return SV_OK;
 }
 
-#endif // STM32F1
+#endif // STM32F1 || ARDUINO_ARCH_STM32
 
 
 /*****************************************************************************
diff --git a/LocoNet.h b/LocoNet.h
index e0c2fb6..8ea28d0 100644
--- a/LocoNet.h
+++ b/LocoNet.h
@@ -335,7 +335,7 @@ class LocoNetFastClockClass
 /************************************************************************************
 	SV (System Variable Handling
 ************************************************************************************/
-#if defined(STM32F1)
+#if defined(STM32F1) || defined(ARDUINO_ARCH_STM32)
 // STM31F1 has no flash.
 #else
 
@@ -490,7 +490,7 @@ class LocoNetSystemVariableClass
 	SV_STATUS doDeferredProcessing(void);
 };
 
-#endif // STM32F1
+#endif // STM32F1 || ARDUINO_ARCH_STM32
 
 class LocoNetCVClass
 {
diff --git a/README.md b/README.md
index 847437f..79b9171 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ It's known to work with:
 - MEGA (ATmega2560)
 - Leonardo, LeoStick, Arduino Pro Micro (ATmega32U4)
 - Various AVRTiny Boards (ATTiny84, ATTiny84A, ATTiny841)
-- Blue Pill (STM32F1 w/ libopencm3 and Arduino Stubs)
+- Blue Pill (STM32F1 w/ libopencm3 and Arduino Stubs, or STM32F3 with stm32duino core)
 - NodeMCU v1.0 (ESP8266 core for Arduino)
 
 As of 2020-03-28 - Hans Tanner added the capability to change the polarity
diff --git a/utility/ln_config.h b/utility/ln_config.h
index 58222be..68ebcb1 100644
--- a/utility/ln_config.h
+++ b/utility/ln_config.h
@@ -55,7 +55,7 @@
  // figure out what board we are building
 
  // Common defines
-#if !defined(STM32F1) && !defined(ESP8266)
+#if !defined(STM32F1) && !defined(ARDUINO_ARCH_STM32) && !defined(ESP8266)
 #  ifdef PINL	//      For the Mega 2560 (should work with 1280, etc)
 #    define _LNET_USE_MEGA
 #  else		//	For the UNO:
@@ -72,7 +72,7 @@
 #  endif
 #endif
 
-#if defined(STM32F1)
+#if defined(STM32F1) || defined(ARDUINO_ARCH_STM32)
 typedef uint32_t LnPortRegisterType;
 typedef uint32_t LnCompareTargetType;
 #else
@@ -97,6 +97,9 @@ typedef volatile LnPortRegisterType* LnPortAddrType;
 #else
 #  if defined(STM32F1)
 #    define LN_BIT_PERIOD             (rcc_apb1_frequency * 2 / 16666)
+#  elif defined(ARDUINO_ARCH_STM32)
+     // TMR2 runs at half the CPU clock on the STM32F3.
+#    define LN_BIT_PERIOD             (36000000 / 16666)
 #  else
 #    define LN_BIT_PERIOD             (F_CPU / 16666)
 #  endif
@@ -209,6 +212,23 @@ defined(__AVR_ATmega1284P__)
 #define LN_TMR_CONTROL_REG    TCCR1B    // the code.
 #define LN_INIT_COMPARATOR() { TCCR1A = 0; TCCR1B = 0x01; }    // no prescaler, normal mode
 
+#elif defined(ARDUINO_ARCH_STM32)
+// This architecture is used for the stm32 core in Arduino (aka stm32duino,
+// also present in the boards manager under 'stm32'. The default settings
+// are for an STM32F303RE (nucleo).
+
+#define LN_RX_PIN_NAME PB14
+#define LN_RX_PORT  (*portInputRegister(GPIOB))
+#define LN_RX_BIT   (14)
+#define LN_RX_BITCFG LL_SYSCFG_EXTI_LINE14
+#define LN_RX_GPIOSEL EXTI_GPIOB
+#define LN_RX_GPIOCFG LL_SYSCFG_EXTI_PORTB
+#define LN_SB_SIGNAL          EXTI15_10_IRQHandler
+#define LN_SB_IRQn            EXTI15_10_IRQn
+#define LN_TMR_SIGNAL         TIM2_IRQHandler
+
+#define ISR(name) extern "C" void name(void)
+
 #elif defined(STM32F1)
 
 #define LN_RX_PIN_NAME PB14
diff --git a/utility/ln_sw_uart.cpp b/utility/ln_sw_uart.cpp
index 920830f..b205a87 100755
--- a/utility/ln_sw_uart.cpp
+++ b/utility/ln_sw_uart.cpp
@@ -51,6 +51,12 @@ extern "C" {
 #  include <libopencm3/stm32/gpio.h>
 #  include <libopencm3/stm32/rcc.h>
 #  include <libopencm3/stm32/timer.h>
+#elif defined(ARDUINO_ARCH_STM32)
+#include <Arduino.h>
+#include <stm32yyxx_ll_system.h>
+#include <stm32yyxx_ll_exti.h>
+#include <stm32yyxx_ll_tim.h>
+/// @todo
 #else
 #  include <avr/io.h>
 #  include <avr/interrupt.h>
@@ -84,7 +90,7 @@ volatile uint8_t  lnTxSuccess;   // this boolean flag as a message from timer in
 volatile uint8_t  lnLastTxBit;
 #endif
 
-#ifndef ESP8266
+#if !defined(ESP8266) && !defined(ARDUINO_ARCH_STM32)
 volatile uint8_t* txPort;
 #else
 LnPortAddrType txPort;
@@ -131,7 +137,7 @@ bool ICACHE_RAM_ATTR isLocoNetCollision()
 }
 #endif
 
-#if defined(STM32F1)
+#if defined(STM32F1) || defined(ARDUINO_ARCH_STM32)
 #  define bit_is_set(PORT, PIN) (((PORT >> PIN) & 0x01) != 0)
 #  define bit_is_clear(PORT, PIN) (((PORT >> PIN) & 0x01) == 0)
 #endif
@@ -160,6 +166,12 @@ ISR(LN_SB_SIGNAL)
 		// Ignore any interrupt that is not EXTI14.
 		return;
 	}
+#elif defined(ARDUINO_ARCH_STM32)
+	// Check if it really was EXTI14 that triggered this interrupt.
+	if (!LL_EXTI_IsActiveFlag_0_31(1u<<LN_RX_BIT)) {
+		// Ignore any interrupt that is not EXTI14.
+		return;
+	}
 #endif
 
 #if defined(ESP8266)
@@ -178,6 +190,10 @@ ISR(LN_SB_SIGNAL)
 	lnCompareTarget = timer_get_counter(TIM2) + LN_TIMER_RX_START_PERIOD;
 	/* Set the initual output compare value for OC1. */
 	timer_set_oc_value(TIM2, TIM_OC1, lnCompareTarget);
+#  elif defined(ARDUINO_ARCH_STM32)
+	lnCompareTarget = LL_TIM_GetCounter(TIM2) + LN_TIMER_RX_START_PERIOD;
+	/* Set the initual output compare value for OC1. */
+	LL_TIM_OC_SetCompareCH1(TIM2, lnCompareTarget & 0xffff);
 #  else  // Get the Current Timer1 Count and Add the offset for the Compare target
 	lnCompareTarget = LN_TMR_INP_CAPT_REG + LN_TIMER_RX_START_PERIOD;
 	LN_TMR_OUTP_CAPT_REG = lnCompareTarget;
@@ -228,8 +244,11 @@ ISR(LN_TMR_SIGNAL)     /* signal handler for timer0 overflow */
 #else
 	LN_CLEAR_TIMER_FLAG();
 	lnCompareTarget += LN_TIMER_RX_RELOAD_PERIOD;
-#  if defined(STM32F1)
+#  if defined(STM32F1) 
 	timer_set_oc_value(TIM2, TIM_OC1, lnCompareTarget);
+#  elif defined(ARDUINO_ARCH_STM32)
+        lnCompareTarget &= 0xffff;
+	LL_TIM_OC_SetCompareCH1(TIM2, lnCompareTarget & 0xffff);
 #  else
 	LN_TMR_OUTP_CAPT_REG = lnCompareTarget;
 #  endif
@@ -345,6 +364,9 @@ ISR(LN_TMR_SIGNAL)     /* signal handler for timer0 overflow */
 #  if defined(STM32F1)
 			lnCompareTarget = timer_get_counter(TIM2) + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
 			timer_set_oc_value(TIM2, TIM_OC1, lnCompareTarget);
+#  elif defined(ARDUINO_ARCH_STM32)
+			lnCompareTarget = LL_TIM_GetCounter(TIM2) + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
+                        LL_TIM_OC_SetCompareCH1(TIM2, lnCompareTarget & 0xffff);
 #  else
 			lnCompareTarget = LN_TMR_COUNT_REG + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
 			LN_TMR_OUTP_CAPT_REG = lnCompareTarget;
@@ -425,7 +447,7 @@ void initLocoNetHardware(LnBuf * RxBuffer)
 	// Set the RX line to Input
 #if defined(ESP8266)
 	pinMode(LN_RX_PORT, INPUT);
-#elif defined(STM32F1)
+#elif defined(STM32F1) || defined(ARDUINO_ARCH_STM32)
 	pinMode(LN_RX_PIN_NAME, INPUT);
 #else
 	cbi(LN_RX_DDR, LN_RX_BIT);
@@ -496,7 +518,51 @@ void initLocoNetHardware(LnBuf * RxBuffer)
 	exti_reset_request(EXTI14);
 	exti_enable_request(EXTI14);
 	nvic_enable_irq(NVIC_EXTI15_10_IRQ);
+#elif defined(ARDUINO_ARCH_STM32)
+
+        // === Setup the timer ===
 
+	// Enable TIM2 clock. 
+        __HAL_RCC_TIM2_CLK_ENABLE();
+
+	// Enable TIM2 interrupt.
+        NVIC_SetPriority(TIM2_IRQn, 0);
+        NVIC_EnableIRQ(TIM2_IRQn);
+
+	// Reset TIM2 peripheral to defaults.
+        __HAL_RCC_TIM2_FORCE_RESET();
+        asm("nop ; nop ; nop; ");
+        __HAL_RCC_TIM2_RELEASE_RESET();
+
+        // Initializes TIM2 timer to count at max speed.
+        TIM_HandleTypeDef TimHandle;
+        memset(&TimHandle, 0, sizeof(TimHandle));
+        TimHandle.Instance = TIM2;
+        TimHandle.Init.Period = 65535;
+        TimHandle.Init.Prescaler = 1;
+        TimHandle.Init.ClockDivision = 0;
+        TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
+        TimHandle.Init.RepetitionCounter = 0;
+        HAL_TIM_Base_Init(&TimHandle);
+        HAL_TIM_Base_Start(&TimHandle);
+        // Disables all interrupts on the timer.
+        TIM2->DIER = 0;
+
+        // Sets up level change interrupt on RX pin.
+        LL_SYSCFG_SetEXTISource(LN_RX_GPIOCFG, LN_RX_BITCFG);
+#  ifdef LN_SW_UART_RX_INVERTED  
+        LL_EXTI_EnableRisingTrig_0_31(LN_EXTI_FLAG);
+#  else
+        LL_EXTI_EnableFallingTrig_0_31(LN_EXTI_FLAG);
+#  endif
+
+	lnState = LN_ST_IDLE;
+
+	LN_CLEAR_START_BIT_FLAG();
+	LN_ENABLE_START_BIT_INTERRUPT();
+        NVIC_SetPriority(LN_SB_IRQn, 0);
+        NVIC_EnableIRQ(LN_SB_IRQn);
+        
 #else
 #  ifdef LN_INIT_COMPARATOR
 	LN_INIT_COMPARATOR();
@@ -525,6 +591,8 @@ void initLocoNetHardware(LnBuf * RxBuffer)
 #  else
 	attachInterrupt(digitalPinToInterrupt(LN_RX_PORT), ln_esp8266_pin_isr, FALLING);
 #  endif
+#elif defined(ARDUINO_ARCH_STM32)
+        // all of these already done above
 #else
 	//Clear StartBit Interrupt flag
 	LN_CLEAR_START_BIT_FLAG();
@@ -538,7 +606,7 @@ void initLocoNetHardware(LnBuf * RxBuffer)
 
 	// Set Timer Clock Source 
 	LN_TMR_CONTROL_REG = (LN_TMR_CONTROL_REG & 0xF8) | LN_TMR_PRESCALER;
-#endif // STM32F1 
+#endif // STM32F1 || ARDUINO_ARCH_STM32
 }
 
 
@@ -609,8 +677,10 @@ LN_STATUS sendLocoNetPacketTry(lnMsg * TxData, unsigned char ucPrioDelay)
 #else
 	// Before we do anything else - Disable StartBit Interrupt
 	LN_DISABLE_START_BIT_INTERRUPT();
-#  if defined(STM32F1)
+#  if defined(STM32F1) 
 	if (exti_get_flag_status(EXTI14)) {
+#  elif defined(ARDUINO_ARCH_STM32)
+	if (LL_EXTI_IsActiveFlag_0_31(1u<<LN_RX_BIT)) {
 #  else
 	if (bit_is_set(LN_SB_INT_STATUS_REG, LN_SB_INT_STATUS_BIT)) {
 #  endif
@@ -640,6 +710,10 @@ LN_STATUS sendLocoNetPacketTry(lnMsg * TxData, unsigned char ucPrioDelay)
 	lnCompareTarget = timer_get_counter(TIM2) + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
 	/* Set the initual output compare value for OC1. */
 	timer_set_oc_value(TIM2, TIM_OC1, lnCompareTarget);
+#  elif defined(ARDUINO_ARCH_STM32)
+	lnCompareTarget = LL_TIM_GetCounter(TIM2) + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
+	/* Set the initual output compare value for OC1. */
+	LL_TIM_OC_SetCompareCH1(TIM2, lnCompareTarget & 0xffff);
 #  else
 	lnCompareTarget = LN_TMR_COUNT_REG + LN_TIMER_TX_RELOAD_PERIOD - LN_TIMER_TX_RELOAD_ADJUST;
 	LN_TMR_OUTP_CAPT_REG = lnCompareTarget;
diff --git a/utility/ln_sw_uart.h b/utility/ln_sw_uart.h
index abe0f2f..9c35bd7 100755
--- a/utility/ln_sw_uart.h
+++ b/utility/ln_sw_uart.h
@@ -43,7 +43,7 @@
 
 #ifdef ESP8266
 #  include <Arduino.h>
-#elif !defined(STM32F1)
+#elif !defined(STM32F1) && !defined(ARDUINO_ARCH_STM32)
 #  include <avr/io.h>
 #  include <avr/interrupt.h>
 #endif
@@ -100,7 +100,28 @@
 #  define LN_ENABLE_TIMER_INTERRUPT() (timer_enable_irq(TIM2, TIM_DIER_CC1IE))
 // Disable Timer Compare Interrupt
 #  define LN_DISABLE_TIMER_INTERRUPT() (timer_disable_irq(TIM2, TIM_DIER_CC1IE))
-#elif !defined(ESP8266)
+
+#elif defined(ARDUINO_ARCH_STM32)
+
+# define LN_EXTI_FLAG (1u << LN_RX_BIT)
+//Clear StartBit Interrupt flag
+#  define LN_CLEAR_START_BIT_FLAG() (LL_EXTI_ClearFlag_0_31(LN_EXTI_FLAG))
+//Enable StartBit Interrupt
+#  define LN_ENABLE_START_BIT_INTERRUPT() (LL_EXTI_EnableIT_0_31(LN_EXTI_FLAG))
+//Disable StartBit Interrupt
+#  define LN_DISABLE_START_BIT_INTERRUPT() (LL_EXTI_DisableIT_0_31(LN_EXTI_FLAG))
+
+// Clear Timer Interrupt Flag
+#  define LN_CLEAR_TIMER_FLAG() (LL_TIM_ClearFlag_CC1(TIM2))
+
+// Enable Timer Compare Interrupt
+#  define LN_ENABLE_TIMER_INTERRUPT() (LL_TIM_EnableIT_CC1(TIM2))
+// Disable Timer Compare Interrupt
+#  define LN_DISABLE_TIMER_INTERRUPT() (LL_TIM_DisableIT_CC1(TIM2))
+
+#elif defined(ESP8266)
+// No common definitions needed for the ESP.
+#else // AVR
 //Clear StartBit Interrupt flag
 #  define LN_CLEAR_START_BIT_FLAG() (sbi( LN_SB_INT_STATUS_REG, LN_SB_INT_STATUS_BIT ))
 //Enable StartBit Interrupt
@@ -117,6 +138,7 @@
 #  define LN_DISABLE_TIMER_INTERRUPT() (cbi( LN_TMR_INT_ENABLE_REG, LN_TMR_INT_ENABLE_BIT ))
 #endif
 
+
 // For now we will simply check that TX and RX ARE NOT THE SAME as our circuit
 // requires the TX signal to be INVERTED.  If they are THE SAME then we have a 
 // Collision.