Add support for SoftwareSerial library

Add support for SoftwareSerial library, from
sandeepmistry#205

Author: ct6502

cores/nRF5/Arduino.h

@@ -29,11 +29,11 @@ extern "C"{
 #define clockCyclesToMicroseconds(a) ( ((a) * 1000L) / (SystemCoreClock / 1000L) )
 #define microsecondsToClockCycles(a) ( (a) * (SystemCoreClock / 1000000L) )
 
-void yield( void ) ;
+void yield( void );
 
 /* sketch */
-void setup( void ) ;
-void loop( void ) ;
+void setup( void );
+void loop( void );
 
 #include "WVariant.h"
 
@@ -92,12 +92,12 @@ void loop( void ) ;
 
 #define bit(b) (1UL << (b))
 
-#define digitalPinToPort(P)        ( &(NRF_GPIO[P]) )
+#define digitalPinToPort(P)        ( NRF_GPIO ) // NRF_P0 = P0.00 - P0.31, NRF_P1 = P1.00 - P1.15 (e.g. nRF52840)
 #define digitalPinToBitMask(P)     ( 1 << g_ADigitalPinMap[P] )
 //#define analogInPinToBit(P)        ( )
-#define portOutputRegister(port)   ( &(port->OUTSET) )
+#define portOutputRegister(port)   ( &(port->OUT) )
 #define portInputRegister(port)    ( &(port->IN) )
-#define portModeRegister(port)     ( &(port->DIRSET) )
+#define portModeRegister(port)     ( &(port->DIR) )
 #define digitalPinHasPWM(P)        ( true )
 
 /*

cores/nRF5/WInterrupts.c

@@ -30,42 +30,46 @@
 #define NUMBER_OF_GPIO_TE 4
 #endif
 
-static voidFuncPtr callbacksInt[NUMBER_OF_GPIO_TE];
-static int8_t channelMap[NUMBER_OF_GPIO_TE];
+static voidFuncPtr callbacksInt[NUMBER_OF_GPIO_TE] = { NULL };
+static int8_t channelMap[NUMBER_OF_GPIO_TE] = { -1 };
 static int enabled = 0;
 
 /* Configure I/O interrupt sources */
 static void __initialize()
 {
-  memset(callbacksInt, 0, sizeof(callbacksInt));
-  memset(channelMap, -1, sizeof(channelMap));
-
   NVIC_DisableIRQ(GPIOTE_IRQn);
   NVIC_ClearPendingIRQ(GPIOTE_IRQn);
-  NVIC_SetPriority(GPIOTE_IRQn, 1);
+  NVIC_SetPriority(GPIOTE_IRQn, 3); // Same priority as Uart
   NVIC_EnableIRQ(GPIOTE_IRQn);
 }
 
 /*
  * \brief Specifies a named Interrupt Service Routine (ISR) to call when an interrupt occurs.
  *        Replaces any previous function that was attached to the interrupt.
  */
-void attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
+int attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
 {
-  if (!enabled) {
-    __initialize();
-    enabled = 1;
-  }
+  uint32_t polarity;
+  uint8_t ch;
 
-  if (pin >= PINS_COUNT) {
-    return;
+  if (pin >= PINS_COUNT)
+  {
+    return -1;
   }
 
   pin = g_ADigitalPinMap[pin];
 
-  uint32_t polarity;
+  switch (mode)
+  {
+    //gpiote channel does not support LOW and HIGH mode. These are mantained for compatibility
+    case LOW:
+      polarity = GPIOTE_CONFIG_POLARITY_HiToLo; //same as FALLING
+    break;
+    
+    case HIGH:
+      polarity = GPIOTE_CONFIG_POLARITY_LoToHi; //same as RISING
+    break;
 
-  switch (mode) {
     case CHANGE:
       polarity = GPIOTE_CONFIG_POLARITY_Toggle;
       break;
@@ -79,11 +83,13 @@ void attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
       break;
 
     default:
-      return;
+      return -1;
   }
 
-  for (int ch = 0; ch < NUMBER_OF_GPIO_TE; ch++) {
-    if (channelMap[ch] == -1 || (uint32_t)channelMap[ch] == pin) {
+  for (ch = 0; ch < NUMBER_OF_GPIO_TE; ch++)
+  {
+    if (channelMap[ch] == -1 || (uint32_t)channelMap[ch] == pin)
+    {
       channelMap[ch] = pin;
       callbacksInt[ch] = callback;
 
@@ -98,6 +104,16 @@ void attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode)
       break;
     }
   }
+
+  // enable the interrupt after the first one is configured
+  if (!enabled)
+  {
+    __initialize();
+    enabled = 1;
+  }
+
+  // return the interrupt mask
+  return (1 << ch);
 }
 
 /*
@@ -127,21 +143,31 @@ void detachInterrupt(uint32_t pin)
 
 void GPIOTE_IRQHandler()
 {
-  uint32_t event = offsetof(NRF_GPIOTE_Type, EVENTS_IN[0]);
-
-  for (int ch = 0; ch < NUMBER_OF_GPIO_TE; ch++) {
-    if ((*(uint32_t *)((uint32_t)NRF_GPIOTE + event) == 0x1UL) && (NRF_GPIOTE->INTENSET & (1 << ch))) {
-      if (channelMap[ch] != -1 && callbacksInt[ch]) {
-        callbacksInt[ch]();
-      }
-
-    *(uint32_t *)((uint32_t)NRF_GPIOTE + event) = 0;
-#if __CORTEX_M == 0x04
-    volatile uint32_t dummy = *((volatile uint32_t *)((uint32_t)NRF_GPIOTE + event));
-    (void)dummy;
-#endif
+  uint32_t event;
+  uint8_t ch;
+
+  for (ch = 0; ch < NUMBER_OF_GPIO_TE; ch++)
+  {
+    event = offsetof(NRF_GPIOTE_Type, EVENTS_IN[ch]);
+    if ((*(uint32_t *)((uint32_t)NRF_GPIOTE + event) == 0x1UL) && (NRF_GPIOTE->INTENSET & (1 << ch)))
+    {
+      break;
     }
-
-    event = (uint32_t)((uint32_t)event + 4);
   }
+
+  // clear event
+  *(uint32_t *)((uint32_t)NRF_GPIOTE + event) = 0;
+  #if __CORTEX_M == 0x04
+  volatile uint32_t dummy = *((volatile uint32_t *)((uint32_t)NRF_GPIOTE + event));
+  (void)dummy;
+  #endif
+  
+  // disable the interrupt
+  NRF_GPIOTE->INTENCLR = (1 << ch);
+
+  // initiate the callback
+  callbacksInt[ch]();
+
+  // enable the interrupt
+  NRF_GPIOTE->INTENSET = (1 << ch);
 }

cores/nRF5/WInterrupts.h

@@ -40,7 +40,7 @@ typedef void (*voidFuncPtr)(void);
  * \brief Specifies a named Interrupt Service Routine (ISR) to call when an interrupt occurs.
  *        Replaces any previous function that was attached to the interrupt.
  */
-void attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode);
+int attachInterrupt(uint32_t pin, voidFuncPtr callback, uint32_t mode);
 
 /*
  * \brief Turns off the given interrupt.

libraries/SoftwareSerial/README.md

@@ -0,0 +1,30 @@
+### SoftwareSerial
+
+This library is based off SoftwareSerial from @arduino-org's arduino-core-nrf52 release [1.0.1](https://github.com/arduino-org/arduino-core-nrf52/releases/tag/1.0.1)
+
+#### Modifications
+* merged SoftwareSerial.cpp into SoftwareSerial.h to allow ```_SS_MAX_RX_BUFF``` to be user-defined
+* added ```_SS_TX_ONLY``` user define to allow this to be used as a transmit only library (no interrupts used)
+
+### License
+
+I do not claim copyright on the code, license taken from SoftwareSerial.h header.
+
+```
+SoftwareSerial.h - library for Arduino Primo
+Copyright (c) 2016 Arduino. All rights reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+```