diff --git a/bacnet-stack/ports/atmega168/Makefile b/bacnet-stack/ports/atmega168/Makefile
index e87f13a7..3322f456 100644
--- a/bacnet-stack/ports/atmega168/Makefile
+++ b/bacnet-stack/ports/atmega168/Makefile
@@ -1,19 +1,27 @@
 ###############################################################################
-# Makefile for the project bacnet
+# Makefile for BACnet
 ###############################################################################
 
 ## General Flags
 PROJECT = bacnet
 MCU = atmega168
-TARGET = bacnet.elf
+TARGET = bacnet
 CC = avr-gcc.exe
 
+CSRC = main.c \
+	timer.c \
+	rs485.c
+
+COBJ = $(CSRC:.c=.o)
+
 ## Options common to compile, link and assembly rules
 COMMON = -mmcu=$(MCU)
+OPTIMIZATION = -O0
+#OPTIMIZATION = -Os
 
 ## Compile options common for all C compilation units.
 CFLAGS = $(COMMON)
-CFLAGS += -Wall -gdwarf-2 -O0
+CFLAGS += -Wall -gdwarf-2 -DF_CPU=7372800UL $(OPTIMIZATION) -fsigned-char
 CFLAGS += -MD -MP -MT $(*F).o -MF dep/$(@F).d 
 
 ## Assembly specific flags
@@ -23,61 +31,51 @@ ASMFLAGS += -x assembler-with-cpp -Wa,-gdwarf2
 
 ## Linker flags
 LDFLAGS = $(COMMON)
-LDFLAGS += 
-
+LDFLAGS += -Wl,-Map=$(TARGET).map
 
 ## Intel Hex file production flags
 HEX_FLASH_FLAGS = -R .eeprom
-
 HEX_EEPROM_FLAGS = -j .eeprom
 HEX_EEPROM_FLAGS += --set-section-flags=.eeprom="alloc,load"
 HEX_EEPROM_FLAGS += --change-section-lma .eeprom=0 --no-change-warnings
 
-
 ## Include Directories
-INCLUDES = -I"C:\code\bacnet-stack\ports\atmega168\..\.." 
+INCLUDES = -I. -I..\.. 
 
 ## Objects that must be built in order to link
-OBJECTS = main.o rs485.o timer.o 
-
-## Objects explicitly added by the user
-LINKONLYOBJECTS = 
+OBJECTS = $(COBJ)
 
 ## Build
-all: $(TARGET) bacnet.hex bacnet.eep size
+TARGET_ELF=$(TARGET).elf
 
-## Compile
-main.o: ../main.c
-	$(CC) $(INCLUDES) $(CFLAGS) -c  $<
-
-rs485.o: ../rs485.c
-	$(CC) $(INCLUDES) $(CFLAGS) -c  $<
-
-timer.o: ../timer.c
-	$(CC) $(INCLUDES) $(CFLAGS) -c  $<
+all: $(TARGET_ELF) $(TARGET).hex $(TARGET).eep size
 
 ##Link
-$(TARGET): $(OBJECTS)
-	 $(CC) $(LDFLAGS) $(OBJECTS) $(LINKONLYOBJECTS) $(LIBDIRS) $(LIBS) -o $(TARGET)
+$(TARGET_ELF): $(OBJECTS)
+	$(CC) $(LDFLAGS) $(OBJECTS) $(LIBDIRS) $(LIBS) -o $@
 
-%.hex: $(TARGET)
+%.hex: $(TARGET_ELF)
 	avr-objcopy -O ihex $(HEX_FLASH_FLAGS)  $< $@
 
-%.eep: $(TARGET)
+%.eep: $(TARGET_ELF)
 	-avr-objcopy $(HEX_EEPROM_FLAGS) -O ihex $< $@ || exit 0
 
-%.lss: $(TARGET)
+%.lss: $(TARGET_ELF)
 	avr-objdump -h -S $< > $@
 
-size: ${TARGET}
+$(COBJ): %.o : %.c Makefile
+	$(CC) -c $(INCLUDES) $(CFLAGS) $< -o $@
+
+size: ${TARGET_ELF}
 	@echo
-	@avr-size -C --mcu=${MCU} ${TARGET}
+	@avr-size -C --mcu=${MCU} ${TARGET_ELF}
 
 ## Clean target
 .PHONY: clean
 clean:
-	-rm -rf $(OBJECTS) bacnet.elf dep/* bacnet.hex bacnet.eep
+	touch Makefile
+	-rm -rf $(OBJECTS) $(TARGET_ELF) dep/* 
+	-rm -rf $(TARGET).hex $(TARGET).eep $(TARGET).lss $(TARGET).map
 
 ## Other dependencies
 -include $(shell mkdir dep 2>/dev/null) $(wildcard dep/*)
-
diff --git a/bacnet-stack/ports/atmega168/bacnet.aps b/bacnet-stack/ports/atmega168/bacnet.aps
index b55ef2a5..2b49780b 100644
--- a/bacnet-stack/ports/atmega168/bacnet.aps
+++ b/bacnet-stack/ports/atmega168/bacnet.aps
@@ -1 +1 @@
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Simulator</CURRENT_TARGET><CURRENT_TARGET>AVR Simulator</CURRENT_TARGET><CURRENT_PART>ATmega168.xml</CURRENT_PART><BREAKPOINTS></BREAKPOINTS><IO_EXPAND></IO_EXPAND><REGISTERNAMES></REGISTERNAMES><COM>Auto</COM><COMType>0</COMType><WATCHNUM>0</WATCHNUM><WATCHNAMES><Pane0></Pane0><Pane1></Pane1><Pane2></Pane2><Pane3></Pane3></WATCHNAMES><BreakOnTrcaeFull>0</BreakOnTrcaeFull></DEBUG_TARGET><Debugger><modules><module></module></modules><Triggers><trigger clsid="{113824F1-C410-4699-A25E-867CC860C28E}" enabled="1" boundTo="0" hitCount="1" updateAndContinue="0" line="68" file="main.c" token="	    Timer_Milliseconds--;" 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GCC</ProjectTypeName></MANAGEMENT><CODE_CREATION><ObjectFile>default\bacnet.elf</ObjectFile><EntryFile></EntryFile><ObjectFile></ObjectFile><EntryFile></EntryFile><SaveFolder>C:\code\bacnet-stack\ports\atmega168\</SaveFolder></CODE_CREATION><DEBUG_TARGET><CURRENT_PART>ATmega168</CURRENT_PART><BREAKPOINTS></BREAKPOINTS><IO_EXPAND><HIDE>false</HIDE></IO_EXPAND><REGISTERNAMES><Register>R00</Register><Register>R01</Register><Register>R02</Register><Register>R03</Register><Register>R04</Register><Register>R05</Register><Register>R06</Register><Register>R07</Register><Register>R08</Register><Register>R09</Register><Register>R10</Register><Register>R11</Register><Register>R12</Register><Register>R13</Register><Register>R14</Register><Register>R15</Register><Register>R16</Register><Register>R17</Register><Register>R18</Register><Register>R19</Register><Register>R20</Register><Register>R21</Register><Register>R22</Register><Register>R23</Register><Register>R24</Register><Register>R25</Register><Register>R26</Register><Register>R27</Register><Register>R28</Register><Register>R29</Register><Register>R30</Register><Register>R31</Register></REGISTERNAMES><CURRENT_TARGET>AVR 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diff --git a/bacnet-stack/ports/atmega168/timer.c b/bacnet-stack/ports/atmega168/timer.c
index 7710a005..d2ce820c 100644
--- a/bacnet-stack/ports/atmega168/timer.c
+++ b/bacnet-stack/ports/atmega168/timer.c
@@ -32,7 +32,7 @@
 /* Count: Timer0 counts up to 0xFF and then signals overflow */
 #define TIMER_TICKS (FREQ_CPU/TIMER_PRESCALER/1000)
 #if (TIMER_TICKS > 0xFF)
-#error Timer Prescaler value too small
+#error Timer Prescaler value is too small
 #endif
 #define TIMER_COUNT (0xFF-TIMER_TICKS)
 /* Global variable millisecond timer - used by main.c for timers task */
@@ -65,13 +65,15 @@ void timer_initialize(void)
     BIT_CLEAR(PRR,PRTIM0);
 }
 
-
+/* Timer interupt */
+/* note: Global interupts must be enabled - sei() */
 /* Timer Overflowed!  Increment the time. */
 ISR(TIMER0_OVF_vect)
 {
     /* Set the counter for the next interrupt */
     TCNT0 = TIMER_COUNT;
     /* Overflow Flag is automatically cleared */
+    /* Update the global timer */
     if (Timer_Milliseconds < 0xFF)
        Timer_Milliseconds++;
 }
diff --git a/bacnet-stack/ports/linux/rs485.c b/bacnet-stack/ports/linux/rs485.c
index 0693c6dd..164f24b6 100644
--- a/bacnet-stack/ports/linux/rs485.c
+++ b/bacnet-stack/ports/linux/rs485.c
@@ -63,7 +63,7 @@ static int RS485_Handle = -1;
    included by <termios.h> */
 static unsigned int RS485_Baud = B38400;
 /* serial port name, /dev/ttyS0,
-  /dev/ttyUSB0 for USB->RS485 from SerialGear or USBGear   */
+  /dev/ttyUSB0 for USB->RS485 from B&B Electronics USOPTL4 */
 static char *RS485_Port_Name = "/dev/ttyUSB0";
 /* serial I/O settings */
 static struct termios RS485_oldtio;