Added end() function to Soft Serial

the basic trick of this commit is to allow to call the new introduced end and again begin as much as wanted,
avoiding to further consume indexes in the nvic interrupt table

Author: maidnl

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 getIrqIndexFromPint(uint32_t pin);
 
 /* Wrapper class for FSP ELC 
     at the present only support the link of an external Irq to a peripheral */

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 getIrqIndexFromPint(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);

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 getIrqIndexFromPint(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 = getIrqIndexFromPint(_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.
@@ -324,9 +337,29 @@ 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 = getIrqIndexFromPint(_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);
+    }
+}
+
 int SoftwareSerial::read()
 {
     int chr = -1;

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__