From 6b9d0c91b925194ed4941f510673962bde57fb46 Mon Sep 17 00:00:00 2001
From: Felix Rusu <felix@lowpowerlab.com>
Date: Thu, 13 Dec 2018 19:39:20 -0500
Subject: [PATCH] Add SPI_Transactions

---
 RFM69.cpp | 13 +++++++++++++
 RFM69.h   |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/RFM69.cpp b/RFM69.cpp
index 937f090..9faa6ed 100644
--- a/RFM69.cpp
+++ b/RFM69.cpp
@@ -108,6 +108,11 @@ bool RFM69::initialize(uint8_t freqBand, uint8_t nodeID, uint8_t networkID)
   digitalWrite(_slaveSelectPin, HIGH);
   pinMode(_slaveSelectPin, OUTPUT);
   SPI.begin();
+  
+#ifdef SPI_HAS_TRANSACTION
+  _settings = SPISettings(4000000, MSBFIRST, SPI_MODE0);
+#endif
+
   unsigned long start = millis();
   uint8_t timeout = 50;
   do writeReg(REG_SYNCVALUE1, 0xAA); while (readReg(REG_SYNCVALUE1) != 0xaa && millis()-start < timeout);
@@ -477,6 +482,11 @@ void RFM69::select() {
   _SPCR = SPCR;
   _SPSR = SPSR;
 #endif
+
+#ifdef SPI_HAS_TRANSACTION
+  SPI.beginTransaction(_settings);
+#endif
+
   // set RFM69 SPI settings
   SPI.setDataMode(SPI_MODE0);
   SPI.setBitOrder(MSBFIRST);
@@ -491,6 +501,9 @@ void RFM69::select() {
 // unselect the RFM69 transceiver (set CS high, restore SPI settings)
 void RFM69::unselect() {
   digitalWrite(_slaveSelectPin, HIGH);
+#ifdef SPI_HAS_TRANSACTION
+  SPI.endTransaction();
+#endif  
   // restore SPI settings to what they were before talking to RFM69
 #if defined (SPCR) && defined (SPSR)
   SPCR = _SPCR;
diff --git a/RFM69.h b/RFM69.h
index 66be994..47cf8c5 100644
--- a/RFM69.h
+++ b/RFM69.h
@@ -224,6 +224,9 @@ class RFM69 {
     uint8_t _SPCR;
     uint8_t _SPSR;
 #endif
+#ifdef SPI_HAS_TRANSACTION
+  SPISettings _settings;
+#endif
 
     virtual void receiveBegin();
     virtual void setMode(uint8_t mode);