diff --git a/AD9833.cpp b/AD9833.cpp
index 7a148d9..b248062 100644
--- a/AD9833.cpp
+++ b/AD9833.cpp
@@ -60,8 +60,15 @@ AD9833 :: AD9833 ( uint8_t FNCpin, uint32_t referenceFrequency ) {
  * This MUST be the first command after declaring the AD9833 object
  * Start SPI and place the AD9833 in the RESET state
  */
-void AD9833 :: Begin ( void ) {
-	SPI.begin();
+void AD9833 :: Begin (SPIClass* spiBus ) {
+
+    if ( spiBus == NULL) {
+        this->_spiBus = &SPI; 
+        _spiBus->begin();
+    } else {
+        this->_spiBus = spiBus;
+        // no begin, assumed SPI is stared outside
+    }
 	delay(100);
 	Reset();	// Hold in RESET until first WriteRegister command
 }
@@ -344,7 +351,10 @@ void AD9833 :: WriteRegister ( int16_t dat ) {
 	/*
 	 * We set the mode here, because other hardware may be doing SPI also
 	 */
-	SPI.setDataMode(SPI_MODE2);
+    const SPISettings settings{200000, MSBFIRST, SPI_MODE2};
+    _spiBus->beginTransaction(settings);
+	// Old:
+    //SPI.setDataMode(SPI_MODE2);
 
 	/* Improve overall switching speed
 	 * Note, the times are for this function call, not the write.
@@ -356,9 +366,11 @@ void AD9833 :: WriteRegister ( int16_t dat ) {
 	//delayMicroseconds(2);	// Some delay may be needed
 
 	// TODO: Are we running at the highest clock rate?
-	SPI.transfer(highByte(dat));	// Transmit 16 bits 8 bits at a time
-	SPI.transfer(lowByte(dat));
+	_spiBus->transfer(highByte(dat));	// Transmit 16 bits 8 bits at a time
+	_spiBus->transfer(lowByte(dat));
 
 	WRITE_FNCPIN(HIGH);		// Write done
+   _spiBus->endTransaction() ;
+   
 }
 
diff --git a/AD9833.h b/AD9833.h
index ba9fd15..8bf5b0f 100644
--- a/AD9833.h
+++ b/AD9833.h
@@ -1,26 +1,28 @@
 /*
  * AD9833.h
- * 
+ *
  * Copyright 2016 Bill Williams <wlwilliams1952@gmail.com, github/BillWilliams1952>
- * 
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
- * 
+ *
  * This program 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 General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  * MA 02110-1301, USA.
- * 
- * 
+ *
+ *
  */
 
+// update
+
 #ifndef __AD9833__
 
 #define __AD9833__
@@ -52,25 +54,27 @@
 
 #define PHASE_WRITE_CMD		0xC000		// Setup for Phase write
 #define PHASE1_WRITE_REG	0x2000		// Which phase register
-#define FREQ0_WRITE_REG		0x4000		// 
+#define FREQ0_WRITE_REG		0x4000		//
 #define FREQ1_WRITE_REG		0x8000
 #define PHASE1_OUTPUT_REG	0x0400		// Output is based off REG0/REG1
 #define FREQ1_OUTPUT_REG	0x0800		// ditto
 
 typedef enum { SINE_WAVE = 0x2000, TRIANGLE_WAVE = 0x2002,
 			   SQUARE_WAVE = 0x2028, HALF_SQUARE_WAVE = 0x2020 } WaveformType;
-			   
+
 typedef enum { REG0, REG1, SAME_AS_REG0 } Registers;
 
 class AD9833 {
 
 public:
-	
+
 	AD9833 ( uint8_t FNCpin, uint32_t referenceFrequency = 25000000UL );
 
 	// Must be the first command after creating the AD9833 object.
-	void Begin ( void );
-
+	// Must be the first command after creating the AD9833 object.
+    // if nothing is given (i.e. NULL) default SPI is used
+	void Begin (SPIClass *spiBus = NULL);
+    
 	// Setup and apply a signal. Note that any calls to EnableOut,
 	// SleepMode, DisableDAC, or DisableInternalClock remain in effect
 	void ApplySignal ( WaveformType waveType, Registers freqReg,
@@ -112,13 +116,13 @@ class AD9833 {
 	// Enable / Disable Internal Clock
 	void DisableInternalClock ( bool enable );
 
-	// Return actual frequency programmed in register 
+	// Return actual frequency programmed in register
 	float GetActualProgrammedFrequency ( Registers reg );
 
 	// Return actual phase programmed in register
 	float GetActualProgrammedPhase ( Registers reg );
 
-	// Return frequency resolution 
+	// Return frequency resolution
 	float GetResolution ( void );
 
 private:
@@ -133,7 +137,7 @@ class AD9833 {
 	uint32_t		refFrequency;
 	float			frequency0, frequency1, phase0, phase1;
 	Registers		activeFreq, activePhase;
+    SPIClass		*_spiBus;
 };
 
 #endif
-