diff --git a/IO_EXIOExpander.h b/IO_EXIOExpander.h
index 1c2c570..2331715 100644
--- a/IO_EXIOExpander.h
+++ b/IO_EXIOExpander.h
@@ -82,31 +82,58 @@ private:
 
   void _setupDevice() {
     // Send digital and analogue pin counts
-    I2CManager.write(_i2cAddress, 3, REG_EXIOINIT, _numDigitalPins, _numAnaloguePins);
-    // Enable digital ports
-    _digitalPinBytes = (_numDigitalPins + 7) / 8 + 1;
-    uint8_t _enableDigitalPins[_digitalPinBytes];
-    _enableDigitalPins[0] = REG_EXIODPIN;
-    for (uint8_t byte = 1; byte < _digitalPinBytes; byte++) {
-      _enableDigitalPins[byte] = 0;
+    uint8_t _setupBuffer[3] = {EXIOINIT, _numDigitalPins, _numAnaloguePins};
+    // I2CManager.write(_i2cAddress, 3, EXIOINIT, _numDigitalPins, _numAnaloguePins);
+    I2CManager.write(_i2cAddress, _setupBuffer, 3, &_i2crb);
+    _activity = EXIODPIN;
+  }
+
+  void _loop(unsigned long currentMicros) override {
+    if (_i2crb.status == I2C_STATUS_PENDING) return;
+    if (_i2crb.status == I2C_STATUS_OK) {
+      switch(_activity) {
+        case EXIODPIN:
+          // Enable digital ports
+          _digitalPinBytes = (_numDigitalPins + 7) / 8 + 1;
+          // uint8_t _enableDigitalPins[_digitalPinBytes];
+          // _enableDigitalPins[0] = EXIODPIN;
+          _digitalOutBuffer[0] = EXIODPIN;
+          for (uint8_t byte = 1; byte < _digitalPinBytes; byte++) {
+            // _enableDigitalPins[byte] = 0;
+            _digitalOutBuffer[byte] = 0;
+          }
+          for (uint8_t pin = 0; pin < _numDigitalPins; pin++) {
+            int pinByte = pin / 8;
+            // bitSet(_enableDigitalPins[pinByte + 1], pin - pinByte * 8);
+            bitSet(_digitalOutBuffer[pinByte + 1], pin - pinByte * 8);
+          }
+          // I2CManager.write(_i2cAddress, _enableDigitalPins, _digitalPinBytes, &_i2crb);
+          I2CManager.write(_i2cAddress, _digitalOutBuffer, _digitalPinBytes, &_i2crb);
+          _activity = EXIOAPIN;
+          break;
+        case EXIOAPIN:
+          // Enable analogue ports
+          _analoguePinBytes = (_numAnaloguePins + 7) / 8 + 1;
+          // uint8_t _enableAnaloguePins[_analoguePinBytes];
+          // _enableAnaloguePins[0] = EXIOAPIN;
+          _analogueOutBuffer[0] = EXIOAPIN;
+          for (uint8_t byte = 1; byte < _analoguePinBytes; byte++) {
+            // _enableAnaloguePins[byte] = 0;
+            _analogueOutBuffer[byte] = 0;
+          }
+          for (uint8_t pin = 0; pin < _numAnaloguePins; pin++) {
+            int pinByte = pin / 8;
+            // bitSet(_enableAnaloguePins[pinByte + 1], pin - pinByte * 8);
+            bitSet(_analogueOutBuffer[pinByte + 1], pin - pinByte * 8);
+          }
+          // I2CManager.write(_i2cAddress, _enableAnaloguePins, _analoguePinBytes, &_i2crb);
+          I2CManager.write(_i2cAddress, _analogueOutBuffer, _analoguePinBytes, &_i2crb);
+          _activity = EXIORDY;
+          break;
+        default:
+          break;
+      }
     }
-    for (uint8_t pin = 0; pin < _numDigitalPins; pin++) {
-      int pinByte = pin / 8;
-      bitSet(_enableDigitalPins[pinByte + 1], pin - pinByte * 8);
-    }
-    I2CManager.write(_i2cAddress, _enableDigitalPins, _digitalPinBytes, &_i2crb);
-    // Enable analogue ports
-    _analoguePinBytes = (_numAnaloguePins + 7) / 8 + 1;
-    uint8_t _enableAnaloguePins[_analoguePinBytes];
-    _enableAnaloguePins[0] = REG_EXIOAPIN;
-    for (uint8_t byte = 1; byte < _analoguePinBytes; byte++) {
-      _enableAnaloguePins[byte] = 0;
-    }
-    for (uint8_t pin = 0; pin < _numAnaloguePins; pin++) {
-      int pinByte = pin / 8;
-      bitSet(_enableAnaloguePins[pinByte + 1], pin - pinByte * 8);
-    }
-    I2CManager.write(_i2cAddress, _enableAnaloguePins, _analoguePinBytes, &_i2crb);
   }
 
   void _display() override {
@@ -119,15 +146,20 @@ private:
   uint8_t _numAnaloguePins;
   int _digitalPinBytes;
   int _analoguePinBytes;
+  uint8_t _digitalOutBuffer[EXIO_NANO_DIGITAL_PINS + 1];
+  uint8_t _digitalInBufer[EXIO_NANO_DIGITAL_PINS];
+  uint8_t _analogueOutBuffer[EXIO_NANO_ANALOGUE_PINS + 1];
+  uint8_t _analogueInBuffer[EXIO_NANO_ANALOGUE_PINS];
+  uint8_t _activity;
   I2CRB _i2crb;
 
   enum {
-    REG_EXIOINIT = 0xE0,    // Flag to initialise setup procedure
-    REG_EXIODPIN = 0xE1,    // Flag we're sending digital pin assignments
-    REG_EXIOAPIN = 0xE2,    // Flag we're sending analogue pin assignments
-    REG_EXIORDY = 0xE3,     // Flag we have completed setup procedure, also for EX-IO to ACK setup
-    REG_EXIODDIR = 0xE4,    // Flag we're sending digital pin direction configuration
-    REG_EXIODPUP = 0xE5,    // Flag we're sending digital pin pullup configuration
+    EXIOINIT = 0xE0,    // Flag to initialise setup procedure
+    EXIODPIN = 0xE1,    // Flag we're sending digital pin assignments
+    EXIOAPIN = 0xE2,    // Flag we're sending analogue pin assignments
+    EXIORDY = 0xE3,     // Flag we have completed setup procedure, also for EX-IO to ACK setup
+    EXIODDIR = 0xE4,    // Flag we're sending digital pin direction configuration
+    EXIODPUP = 0xE5,    // Flag we're sending digital pin pullup configuration
   };
 };