diff --git a/IO_TM1638.cpp b/IO_TM1638.cpp
new file mode 100644
index 0000000..395d745
--- /dev/null
+++ b/IO_TM1638.cpp
@@ -0,0 +1,127 @@
+/*
+ *  © 2024, Chris Harlow. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It 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 CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <Arduino.h>
+#include "IODevice.h"
+#include "DIAG.h"
+#include "IO_TM1638.h"
+#include "TM1638x.h"
+   
+const uint8_t HIGHFLASH _digits[16]={
+      0b00111111,0b00000110,0b01011011,0b01001111,
+      0b01100110,0b01101101,0b01111101,0b00000111,
+      0b01111111,0b01101111,0b01110111,0b01111100,
+      0b00111001,0b01011110,0b01111001,0b01110001
+    };
+
+  // Constructor
+   TM1638::TM1638(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin){
+    _firstVpin = firstVpin;
+    _nPins = 8;
+    tm=new TM1638x(clk_pin,dio_pin,stb_pin);
+    _buttons=0;
+    _leds=0;
+    _lastLoop=micros();
+    addDevice(this);
+   } 
+
+    
+  void TM1638::create(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin) {
+    if (checkNoOverlap(firstVpin,8)) 
+     new TM1638(firstVpin, clk_pin,dio_pin,stb_pin); 
+  }
+
+  void TM1638::_begin()  {
+    tm->reset();
+    tm->test();
+    _display();
+  }
+  
+ 
+  void TM1638::_loop(unsigned long currentMicros)  {
+     if (currentMicros - _lastLoop > (1000000UL/LoopHz)) {
+         _buttons=tm->getButtons();// Read the buttons
+         _lastLoop=currentMicros;
+     }
+     // DIAG(F("TM1638 buttons %x"),_buttons); 
+  }
+           
+  void TM1638::_display()  {
+    DIAG(F("TM1638 Configured on Vpins:%u-%u"), _firstVpin, _firstVpin+_nPins-1);
+  }
+
+// digital read gets button state 
+int TM1638::_read(VPIN vpin)  {
+  byte pin=vpin - _firstVpin;
+  bool result=bitRead(_buttons,pin);
+  // DIAG(F("TM1638 read (%d) buttons %x = %d"),pin,_buttons,result);  
+  return result;
+}
+
+// digital write sets led state 
+void TM1638::_write(VPIN vpin, int value)  {
+  // TODO.. skip if no state change  
+  tm->writeLed(vpin - _firstVpin + 1,value!=0);
+  }
+
+// Analog write sets digit displays 
+
+void TM1638::_writeAnalogue(VPIN vpin, int lowBytes, uint8_t mode, uint16_t highBytes)  {  
+   DIAG(F("TM1638 w(v=%d,l=%d,m=%d,h=%d,lx=%x,hx=%x"),
+   vpin,lowBytes,mode,highBytes,lowBytes,highBytes);
+   // mode is in DataFormat defined above.
+   byte formatLength=mode & 0x0F;  // last 4 bits 
+   byte formatType=mode & 0xF0;         //           
+   int8_t leftDigit=vpin-_firstVpin; // 0..7 from left
+   int8_t rightDigit=leftDigit+formatLength-1; // 0..7 from left
+   
+   // loading is done right to left startDigit first
+   int8_t startDigit=7-rightDigit; // reverse as 7 on left
+   int8_t lastDigit=7-leftDigit; // reverse as 7 on left
+   uint32_t value=highBytes;
+   value<<=16;
+   value |= (uint16_t)lowBytes;
+   
+   DIAG(F("TM1638 fl=%d ft=%x sd=%d ld=%d v=%l vx=%X"),
+   formatLength,formatType,
+   startDigit,lastDigit,value,value);
+    while(startDigit<=lastDigit) {
+        switch (formatType) {
+            case _DF_DECIMAL:// decimal (leading zeros)
+                tm->displayDig(startDigit,GETHIGHFLASH(_digits,(value%10))); 
+                value=value/10;
+                break; 
+            case _DF_HEX:// HEX (leading zeros)
+                tm->displayDig(startDigit,GETHIGHFLASH(_digits,(value & 0x0F))); 
+                value>>=4;
+                break;  
+            case _DF_RAW:// Raw 7-segment pattern 
+                tm->displayDig(startDigit,value & 0xFF); 
+                value>>=8;
+                break;
+            default:
+                DIAG(F("TM1368 invalid mode 0x%x"),mode);
+                return;
+            }
+    startDigit++;
+    } 
+     
+}
+
+
diff --git a/IO_TM1638.h b/IO_TM1638.h
index 388ce95..beb3ead 100644
--- a/IO_TM1638.h
+++ b/IO_TM1638.h
@@ -32,19 +32,10 @@ private:
     uint8_t _leds;
     unsigned long _lastLoop;
     static const int LoopHz=20; 
-
-private:
+    
   // Constructor
-   TM1638(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin){
-    _firstVpin = firstVpin;
-    _nPins = 8;
-    tm=new TM1638x(clk_pin,dio_pin,stb_pin);
-    _buttons=0;
-    _leds=0;
-    _lastLoop=micros();
-    addDevice(this);
-   } 
-  
+   TM1638(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin);
+
 public:
   enum DigitFormat : byte {
     // last 4 bits are length.
@@ -61,89 +52,17 @@ public:
     //  bits of data conversion type  (ored with length) 
     _DF_DECIMAL=0x00,// right adjusted decimal unsigned leading zeros
     _DF_HEX=0x10,    // right adjusted hex leading zeros 
-    _DF_RAW=0x20,    // bytes are raw 7-segment pattern (max length 4)
+    _DF_RAW=0x20 // bytes are raw 7-segment pattern (max length 4)
   };
 
-  static void create(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin) {
-    if (checkNoOverlap(firstVpin,8)) 
-     new TM1638(firstVpin, clk_pin,dio_pin,stb_pin); 
-  }
-
-  void _begin() override {
-    tm->reset();
-    tm->test();
-    _display();
-  }
+  static void create(VPIN firstVpin, byte clk_pin,byte dio_pin,byte stb_pin);
   
- 
-  void _loop(unsigned long currentMicros) override {
-     if (currentMicros - _lastLoop > (1000000UL/LoopHz)) {
-         _buttons=tm->getButtons();// Read the buttons
-         _lastLoop=currentMicros;
-     }
-     // DIAG(F("TM1638 buttons %x"),_buttons); 
-  }
-           
-  void _display() override {
-    DIAG(F("TM1638 Configured on Vpins:%u-%u"), _firstVpin, _firstVpin+_nPins-1);
-  }
-
-// digital read gets button state 
-int _read(VPIN vpin) override {
-  byte pin=vpin - _firstVpin;
-  bool result=bitRead(_buttons,pin);
-  // DIAG(F("TM1638 read (%d) buttons %x = %d"),pin,_buttons,result);  
-  return result;
-}
-
-// digital write sets led state 
-void _write(VPIN vpin, int value) override {
-  // TODO.. skip if no state change  
-  tm->writeLed(vpin - _firstVpin + 1,value!=0);
-  }
-
-// Analog write sets digit displays 
-
-void _writeAnalogue(VPIN vpin, int lowBytes, uint8_t mode, uint16_t highBytes) override {  
-   DIAG(F("TM1638 w(v=%d,l=%d,m=%d,h=%d,lx=%x,hx=%x"),
-   vpin,lowBytes,mode,highBytes,lowBytes,highBytes);
-   // mode is in DataFormat defined above.
-   byte formatLength=mode & 0x0F;  // last 4 bits 
-   byte formatType=mode & 0xF0;         //           
-   int8_t leftDigit=vpin-_firstVpin; // 0..7 from left
-   int8_t rightDigit=leftDigit+formatLength-1; // 0..7 from left
-   
-   // loading is done right to left startDigit first
-   int8_t startDigit=7-rightDigit; // reverse as 7 on left
-   int8_t lastDigit=7-leftDigit; // reverse as 7 on left
-   uint32_t value=highBytes;
-   value<<=16;
-   value |= (uint16_t)lowBytes;
-   
-   DIAG(F("TM1638 fl=%d ft=%x sd=%d ld=%d v=%l vx=%X"),
-   formatLength,formatType,
-   startDigit,lastDigit,value,value);
-    while(startDigit<=lastDigit) {
-        switch (formatType) {
-            case _DF_DECIMAL:// decimal (leading zeros)
-                tm->displayVal(startDigit,value%10); 
-                value=value/10;
-                break; 
-            case _DF_HEX:// HEX (leading zeros)
-                tm->displayVal(startDigit,value & 0x0F); 
-                value>>=4;
-                break;  
-            case _DF_RAW:// Raw 7-segment pattern 
-                tm->displayDig(startDigit,value & 0xFF); 
-                value>>=8;
-                break;
-            default:
-                DIAG(F("TM1368 invalid mode 0x%x"),mode);
-                return;
-            }
-    startDigit++;
-    } 
-     
-}
+  // Functions overridden in IODevice
+  void _begin();
+  void _loop(unsigned long currentMicros) override ;
+  void _writeAnalogue(VPIN vpin, int value, uint8_t param1, uint16_t param2) override;
+  void _display() override ;
+  int _read(VPIN pin) override;
+  void _write(VPIN pin,int value) override;
 };
-#endif // IO_TM1638_h
+#endif
diff --git a/TM1638x.cpp b/TM1638x.cpp
index 7df23b9..45c8625 100644
--- a/TM1638x.cpp
+++ b/TM1638x.cpp
@@ -2,10 +2,6 @@
 #include "TM1638x.h"
 #include "DIAG.h"
 
-bool TM1638x::getButton(button_t s){
-  _buttons = getButtons();
-  return bitRead(_buttons, s);
-}
 
 // buttons K3/KS1-8
 uint8_t TM1638x::getButtons(){
@@ -38,14 +34,6 @@ void TM1638x::reset(){
   digitalWrite(_stb_pin, HIGH);
 }
 
-void TM1638x::displayVal(uint8_t digitId, uint8_t val){
-  DIAG(F("TM1638x displayVal(%d,%d)"),digitId,val);
-  if ((digitId>7) | (val>15) | (val<0)) return;
-  setDisplayMode(DISPLAY_TURN_ON | _pulse);
-  setDataInstruction(INSTRUCTION_WRITE_DATA| INSTRUCTION_ADDRESS_FIXED);
-  writeDataAt(FIRST_DISPLAY_ADDRESS+14-(digitId*2), _digits[val]);
-}
-
 void TM1638x::displayDig(uint8_t digitId, uint8_t pgfedcba){
   if (digitId>7) return;
   setDisplayMode(DISPLAY_TURN_ON | _pulse);
@@ -69,15 +57,6 @@ void TM1638x::writeLed(uint8_t num,bool state){
   writeDataAt(FIRST_DISPLAY_ADDRESS + (num*2-1), state);
 }
 
-void TM1638x::writeLeds(uint8_t val){
-  setDisplayMode(DISPLAY_TURN_ON | _pulse);
-  setDataInstruction(INSTRUCTION_WRITE_DATA | INSTRUCTION_ADDRESS_FIXED);
-  for(uint8_t i=1;i<9;i++){
-    writeDataAt(FIRST_DISPLAY_ADDRESS + (i*2-1), val & 0x01);
-    val >>= 1; 
-  }
-}
-
 void TM1638x::displayTurnOn(){
   setDisplayMode(DISPLAY_TURN_ON | _pulse);
   _isOn = true;
diff --git a/TM1638x.h b/TM1638x.h
index baaa9d6..6bbb23d 100644
--- a/TM1638x.h
+++ b/TM1638x.h
@@ -50,12 +50,6 @@ class TM1638x{
     #define DISPLAY_TURN_OFF 0x80
     #define DISPLAY_TURN_ON 0x88
 
-    uint8_t _digits[16]={
-      0b00111111,0b00000110,0b01011011,0b01001111,
-      0b01100110,0b01101101,0b01111101,0b00000111,
-      0b01111111,0b01101111,0b01110111,0b01111100,
-      0b00111001,0b01011110,0b01111001,0b01110001
-    };
         
     uint8_t _clk_pin;
     uint8_t _stb_pin;
@@ -80,12 +74,6 @@ class TM1638x{
       digitalWrite(dio_pin, HIGH);    
     }
 
-    /**
-    * @fn getButton
-    * @param s num of button (S1-S8)
-    * @return state of button
-    */
-    bool getButton(button_t s);
     /**
     * @fn getButtons
     * @return state of 8 buttons
@@ -99,22 +87,7 @@ class TM1638x{
     * @param state (true or false)
     */
     void writeLed(uint8_t num, bool state);
-
-    /**
-    * @fn writeLeds
-    * @brief set all 8 leds ON or OFF
-    * @param val 8bits
-    */
-    void writeLeds(uint8_t val);
-
-    /**
-    * @fn displayVal
-    * @brief put value on 7 segment display
-    * @param digitId num of digit(0-7)
-    * @param val value(0->F)
-    */
-    void displayVal(uint8_t digitId, uint8_t val);
-        
+    
     
     /**
     * @fn displayDig