diff --git a/cores/arduino/FspLinkIrq.h b/cores/arduino/FspLinkIrq.h
index 32f7af212..7803c8156 100644
--- a/cores/arduino/FspLinkIrq.h
+++ b/cores/arduino/FspLinkIrq.h
@@ -16,6 +16,7 @@ typedef enum {
 
 extern int attachIrq2Link(uint32_t pin, PinStatus mode);
 extern int detachIrq2Link(pin_size_t pinNumber);
+extern int getIrqIndexFromPin(uint32_t pin);
 
 /* Wrapper class for FSP ELC 
     at the present only support the link of an external Irq to a peripheral */
diff --git a/cores/arduino/Interrupts.cpp b/cores/arduino/Interrupts.cpp
index a01b79fa5..eb9b782e3 100644
--- a/cores/arduino/Interrupts.cpp
+++ b/cores/arduino/Interrupts.cpp
@@ -193,6 +193,21 @@ void attachInterrupt(pin_size_t pinNumber, voidFuncPtr func, PinStatus mode) {
     attachInterruptParam(pinNumber, (voidFuncPtrParam)func, mode, NULL);
 }
 
+
+int getIrqIndexFromPin(uint32_t pinNumber) {
+    CIrq *irq_context = nullptr;
+    int rv = -1;
+    int ch = pin2IrqChannel(pinNumber);
+    if(ch >= 0 && ch < MAX_IRQ_CHANNEL) {
+        irq_context = IrqChannel.get(ch,false);
+        if(irq_context != nullptr) {
+            rv = irq_context->cfg.irq;
+        }
+    }
+    return rv;   
+}
+
+
 int attachIrq2Link(uint32_t pinNumber, PinStatus mode) {
     CIrq *irq_context = nullptr;
     int ch = pin2IrqChannel(pinNumber);
diff --git a/libraries/SoftwareSerial/src/SoftwareSerial.cpp b/libraries/SoftwareSerial/src/SoftwareSerial.cpp
index 255c601f7..7917c993b 100644
--- a/libraries/SoftwareSerial/src/SoftwareSerial.cpp
+++ b/libraries/SoftwareSerial/src/SoftwareSerial.cpp
@@ -48,6 +48,7 @@ void dma_tx_callback(dmac_callback_args_t *args);
 void dma_rx_callback(dmac_callback_args_t *args);
 
 extern int attachIrq2Link(uint32_t pin, PinStatus mode);
+extern int getIrqIndexFromPin(uint32_t pin);
 typedef void (*fsp_dma_callback_t) (dmac_callback_args_t *args);
 
 static uint32_t tx_get_sample(bsp_io_port_pin_t tx, ioport_size_t value)
@@ -192,6 +193,7 @@ SoftwareSerial::SoftwareSerial(uint8_t rx_pin, uint8_t tx_pin, size_t bufsize):
     assert(rx_pin < NUM_DIGITAL_PINS);
     _tx_pin = tx_pin;
     _rx_pin = rx_pin;
+    initialized = false;
 }
 
 SoftwareSerial::~SoftwareSerial()
@@ -228,17 +230,26 @@ int SoftwareSerial::begin(uint32_t baudrate, uint32_t sconfig, bool inverted)
             IOPORT_CFG_PORT_DIRECTION_OUTPUT | IOPORT_CFG_PORT_OUTPUT_HIGH);
     #endif
 
+    /* TX pin configuration */
+
     R_IOPORT_PinCfg(&g_ioport_ctrl, tx_descr.pin, IOPORT_CFG_PORT_DIRECTION_OUTPUT
             | IOPORT_CFG_PULLUP_ENABLE | IOPORT_CFG_PORT_OUTPUT_HIGH);
 
-    // Enable RX pin IRQ.
-    rx_descr.irq_chan = attachIrq2Link(_rx_pin, CHANGE);
-    if (rx_descr.irq_chan != -1) {
-        // TODO: workaround for the core not setting pull-ups.
-        R_IOPORT_PinCfg(&g_ioport_ctrl, rx_descr.pin, IOPORT_CFG_PORT_DIRECTION_INPUT
-                | IOPORT_CFG_PULLUP_ENABLE | IOPORT_CFG_IRQ_ENABLE);
+    /* RX pin configuration */
+
+    /* avoid to call attachIrq2Link if already used because it "consumes" irq
+       indexes in the NVIC */
+    int irq_index = getIrqIndexFromPin(_rx_pin);
+    if(irq_index == -1) {
+        rx_descr.irq_chan = attachIrq2Link(_rx_pin, CHANGE); // Enable RX pin IRQ.
+    } else {
+        R_BSP_IrqEnable ((IRQn_Type)irq_index);
     }
 
+    R_IOPORT_PinCfg(&g_ioport_ctrl, rx_descr.pin, IOPORT_CFG_PORT_DIRECTION_INPUT
+                | IOPORT_CFG_PULLUP_ENABLE | IOPORT_CFG_IRQ_ENABLE);
+
+
     // Set serial configuration.
     config.bitshift = (rx_descr.pin & 0xFF);
     config.polarity = (inverted) ? 1 : 0;
@@ -279,34 +290,36 @@ int SoftwareSerial::begin(uint32_t baudrate, uint32_t sconfig, bool inverted)
     // be calculated, and the start/stop samples can be prepopulated in the DMA TX buffer.
     config.nsamples = (1 + config.databits + (!!config.parity) + config.stopbits);
 
-    // Prepopulate start and stop bits samples.
-    tx_descr.dmabuf[0][0] = tx_get_sample(tx_descr.pin, 0);
-    for (size_t i=0; i<config.stopbits; i++) {
-        tx_descr.dmabuf[0][config.nsamples-1-i] = tx_get_sample(tx_descr.pin, 1);
-    }
+    if(!initialized) {
+        // Prepopulate start and stop bits samples.
+        tx_descr.dmabuf[0][0] = tx_get_sample(tx_descr.pin, 0);
+        for (size_t i=0; i<config.stopbits; i++) {
+            tx_descr.dmabuf[0][config.nsamples-1-i] = tx_get_sample(tx_descr.pin, 1);
+        }
 
-    // Configure the TX DMA and its tigger timer.
-    R_PORT0_Type *tx_port = SS_PORT_ADDR(((tx_descr.pin >> 8) & 0xFF));
-    if (fsp_tim_config(&tx_descr.tim, config.baudrate, false) != 0) {
-        return 0;
-    }
+        // Configure the TX DMA and its tigger timer.
+        R_PORT0_Type *tx_port = SS_PORT_ADDR(((tx_descr.pin >> 8) & 0xFF));
+        if (fsp_tim_config(&tx_descr.tim, config.baudrate, false) != 0) {
+            return 0;
+        }
 
-    if (fsp_dma_config(&tx_descr.dma, SS_DMA_CHANNEL_TX,
-        fsp_tim_to_elc_event(tx_descr.tim.get_channel()), tx_descr.dmabuf[0],
-        (void *) &tx_port->PCNTR3, config.nsamples, dma_tx_callback, this) != 0) {
-        return 0;
-    }
+        if (fsp_dma_config(&tx_descr.dma, SS_DMA_CHANNEL_TX,
+            fsp_tim_to_elc_event(tx_descr.tim.get_channel()), tx_descr.dmabuf[0],
+            (void *) &tx_port->PCNTR3, config.nsamples, dma_tx_callback, this) != 0) {
+            return 0;
+        }
 
-    // Configure the RX DMA and its trigger timer.
-    R_PORT0_Type *rx_port = SS_PORT_ADDR(((rx_descr.pin >> 8) & 0xFF));
-    if (fsp_tim_config(&rx_descr.tim, config.baudrate, true) != 0) {
-        return 0;
-    }
+        // Configure the RX DMA and its trigger timer.
+        R_PORT0_Type *rx_port = SS_PORT_ADDR(((rx_descr.pin >> 8) & 0xFF));
+        if (fsp_tim_config(&rx_descr.tim, config.baudrate, true) != 0) {
+            return 0;
+        }
 
-    if (fsp_dma_config(&rx_descr.dma, SS_DMA_CHANNEL_RX,
-        fsp_tim_to_elc_event(rx_descr.tim.get_channel()), rx_descr.dmabuf[0],
-        (void *) &rx_port->PCNTR2, config.nsamples, dma_rx_callback, this) != 0) {
-        return 0;
+        if (fsp_dma_config(&rx_descr.dma, SS_DMA_CHANNEL_RX,
+            fsp_tim_to_elc_event(rx_descr.tim.get_channel()), rx_descr.dmabuf[0],
+            (void *) &rx_port->PCNTR2, config.nsamples, dma_rx_callback, this) != 0) {
+            return 0;
+        }
     }
 
     // Configure and enable the ELC.
@@ -324,6 +337,27 @@ int SoftwareSerial::begin(uint32_t baudrate, uint32_t sconfig, bool inverted)
             tx_descr.pin, rx_descr.pin, config.bitshift, (config.polarity) ? "Inverted" : "Normal",
             config.nsamples, config.baudrate, config.databits, parity_tostr[config.parity], config.stopbits);
     #endif
+
+    initialized = true;
+    return 1;
+}
+
+int SoftwareSerial::end() {
+    int irq_index = getIrqIndexFromPin(_rx_pin);
+
+    if(irq_index != -1) {
+        R_BSP_IrqDisable((IRQn_Type)irq_index);
+        R_BSP_IrqStatusClear((IRQn_Type)irq_index);
+    }
+
+    if(initialized) {
+        // put rx and tx pin as input
+        R_IOPORT_PinCfg(&g_ioport_ctrl, tx_descr.pin, IOPORT_CFG_PORT_DIRECTION_INPUT);
+        R_IOPORT_PinCfg(&g_ioport_ctrl, rx_descr.pin, IOPORT_CFG_PORT_DIRECTION_INPUT);
+
+        R_ELC_Disable(&elc_ctrl);
+        R_ELC_Close(&elc_ctrl);
+    }
     return 1;
 }
 
diff --git a/libraries/SoftwareSerial/src/SoftwareSerial.h b/libraries/SoftwareSerial/src/SoftwareSerial.h
index e62cac7e1..e1cde125a 100644
--- a/libraries/SoftwareSerial/src/SoftwareSerial.h
+++ b/libraries/SoftwareSerial/src/SoftwareSerial.h
@@ -70,6 +70,7 @@ class SoftwareSerial : public Stream, public arduino::Printable {
         ss_descr_t<2> rx_descr;
         uint8_t _tx_pin, _rx_pin;
         void rx_process();
+        bool initialized;
 
     public:
         using Print::write;
@@ -83,6 +84,7 @@ class SoftwareSerial : public Stream, public arduino::Printable {
         int peek();
         virtual size_t write(uint8_t byte);
         virtual int available();
+        virtual int end();
 };
 
 #endif  //__SOFTWARE_SERIAL_H__