diff --git a/src/PortMCP23S17.cpp b/src/PortMCP23S17.cpp
index 3dbc75c..c8f0919 100644
--- a/src/PortMCP23S17.cpp
+++ b/src/PortMCP23S17.cpp
@@ -30,6 +30,7 @@ void PortMCP23S17::beginProtocol()
     SPI.begin();
     SPI.beginTransaction( SPISettings(5000000, MSBFIRST, SPI_MODE0) ); //control SPI bus, 5 MHz
     //SPI.endTransaction() not called to release SPI bus because keyboard only has one SPI device
+    //if two IOEs are used, move beginTransaction() endTransaction() to write() read() functions
 }
 
 /* begin() is called from Scanner_IOE::begin().
@@ -49,8 +50,8 @@ void PortMCP23S17::begin(const uint8_t strobeOn)
         pullUp = 0;
     }
 
-    transfer(DEVICE_ADDR << 1, portNum, readPins); //configure IODIR
-    transfer(DEVICE_ADDR << 1, portNum + 0x0C, pullUp); //configure GPPU
+    transfer(deviceAddr << 1, portNum, readPins); //configure IODIR
+    transfer(deviceAddr << 1, portNum + 0x0C, pullUp); //configure GPPU
 }
 
 /* write() sets pin output to logicLevel (useful for strobePin, one LED pin, or multiple pins).
@@ -69,12 +70,12 @@ void PortMCP23S17::write(const uint8_t pin, const bool logicLevel)
         outputVal |= pin;                  //set pin output to high
     }
 
-    transfer(DEVICE_ADDR << 1, portNum + 0x12, outputVal); //set GPIO port to outputVal
+    transfer(deviceAddr << 1, portNum + 0x12, outputVal); //set GPIO port to outputVal
 }
 
 /* read() returns portState.  Only portState pins with pull resistors are valid.
 */
 uint8_t PortMCP23S17::read()
 {
-    return transfer( (DEVICE_ADDR << 1) | 1, portNum + 0x12, 0); //read from GPIO
+    return transfer( (deviceAddr << 1) | 1, portNum + 0x12, 0); //read from GPIO
 }
diff --git a/src/PortMCP23S17.h b/src/PortMCP23S17.h
index fc376f0..0a5ad80 100644
--- a/src/PortMCP23S17.h
+++ b/src/PortMCP23S17.h
@@ -36,14 +36,14 @@ MCP23S17 data sheet
 class PortMCP23S17 : public PortInterface
 {
     private:
-        static const uint8_t DEVICE_ADDR;
+        const uint8_t deviceAddr;
         const uint8_t portNum;                  //port identification number
         uint8_t outputVal;                      //bit pattern for strobe and LEDs
         const uint8_t readPins;                 //bits, IODIR 0=output, 1=input
         uint8_t transfer(const uint8_t command, const uint8_t registerAddr, const uint8_t data);
     public:
-        PortMCP23S17(const uint8_t portNum, const uint8_t readPins)
-            : portNum(portNum), outputVal(0), readPins(readPins) {}
+        PortMCP23S17(const uint8_t deviceAddr, const uint8_t portNum, const uint8_t readPins)
+            : deviceAddr(deviceAddr), portNum(portNum), outputVal(0), readPins(readPins) {}
         void beginProtocol();
         void begin(const uint8_t strobeOn);
         virtual void write(const uint8_t pin, const bool logicLevel);
diff --git a/tutorials/keybrd_5b_LED_on_IOE/keybrd_5b_LED_on_IOE.ino b/tutorials/keybrd_5b_LED_on_IOE/keybrd_5b_LED_on_IOE.ino
index 7494075..ec82be8 100644
--- a/tutorials/keybrd_5b_LED_on_IOE/keybrd_5b_LED_on_IOE.ino
+++ b/tutorials/keybrd_5b_LED_on_IOE/keybrd_5b_LED_on_IOE.ino
@@ -46,9 +46,9 @@ LED_uC LED_CapsLck(21);
 
 // =============== RIGHT ===============
 // --------------- RIGHT SCANNER ---------------
-const uint8_t PortMCP23S17::DEVICE_ADDR = 0x20; //MCP23S17 address, all 3 ADDR pins are grounded
-PortMCP23S17 portA(0, 1<<0 | 1<<1 );            //for read and LED
-PortMCP23S17 portB(1, 0);                       //for strobe and LED
+const uint8_t IOE_ADDR = 0x20;                  //MCP23S17 address, all 3 ADDR pins are grounded
+PortMCP23S17 portA(IOE_ADDR, 0, 1<<0 | 1<<1 );  //for read and LED
+PortMCP23S17 portB(IOE_ADDR, 1, 0);             //for strobe and LED
 
 Scanner_IOE scanner_R(LOW, portB, portA);