Before plugging the USB adapter into a USB port for the first time, make sure that you do not attach any serial device to the adapter.

If the O/S in your laptop is Windows Vista, you may not need to install the driver by yourself, just plug the USB adapter into a USB port and let the Vista search the driver for you. Most likely the Vista will download and install it automatically.

If the Vista O/S in your laptop did not install the driver by itself or the O/S in your laptop is Windows XP, or Windows 2000, or Windows 98, you need to download and install the newest driver from the following manufacturer’s web site:

http://www.prolific.com.tw/eng/downloads.asp?ID=31

The newest file name is PL2303_Prolific_DriverInstaller_v1417.zip.
 

Verifying the Installation:

To verify if the adapter is properly installed and determine the COM port assignment of the adapter by Device Manager:  

1. For Windows XP, Windows 2000, Windows ME, or Windows 98:  Click Start -> Control Panel -> System -> Hardware -> Device Manager.  Double-click on Ports (COM & LPT1).
   
   For Windows Vista:  Click Start -> Computer -> System Properties -> Device Manager. Double-click on Ports (COM & LPT1). 
   
   In the following picture you should see the Prolific USB-to-Serial Com Port (COM26) under the Ports. This also means that the Device Manager has assigned the adapter to COM26 port.
   
   
   
   
   
   Note: The COM port assignment of the USB to Serial adapter varies on your PC hardware configuration.
               Windows will randomly assign a unused COM port number to the adapter. 
               The COM26 is just an example here and it could be a different COM port on your PC.
   
   
   
   
2. The IDE software in your PC might not work with COM26 so you may need to reassign the COM Port of the adapter to another port number to work with your IDE. You can double-click on the device shown on the above picture, Prolific USB-to-Serial Comm Port (COM26) to view properties as shown below:
   
   
   
   
   
   
3. Inside the USB-to-Serial Comm Port Properties, click on the Driver tab, make sure that the driver you installed is the newest version 2.0.9.122 dated on 7/6/2009 on XP or 3.3.5.122 dated on 7/17/2009 on Vista. If it's an old driver version, then click on the Update Driver tab, the Windows XP and Vista OS will search web and download the newest driver and install it on your PC automatically. If you have a Windows 98 or ME OS then you may have to download the driver manually from the Prolific's web site before continuing to the step 4. You may also have to uninstall the old driver (check the box says "Delete driver software for this device" before un-install it).
   
   Until you successfully installed the newest driver you do not need to continue to the step 4.
   
   
   
   
   
   
   
4. To reassign the COM port number, click on the Port Settings tab, then click on the Advanced button.
   
   
   
   
   
   
   
   

5.       Inside the Advanced Settings, select lower settings for Receive Buffer and Transmit Buffer
   
    
   
   
   
   

6. Inside the Advanced Settings, click on the COM Port Number and check what other port numbers are unused. If you know what COM port that the IDE uses in your PC, you can just reassign the COM port of the adapter to that COM port number, otherwise you may try to reassign it to COM1 or COM2. Click OK when finished. If your PC indicates that COM1 or COM2 are not available but you know they are available, you can ignore your PC's warning and just select COM1 or COM2 anyway.
   
   
   
   Note: Some DOS programs may only support COM1 and COM2, they may not work if the port is assigned to COM3 and higher.
   
   
   
   

7.       You need to make sure that the COM port number that is assigned by the IDE software in your PC matches the COM port number that is assigned to the USB adapter by Windows OS.
   
   Once you have verified that the USB adapter is properly installed, you may now connect the adapter to your development board.  
   
   

• Once you have verified that the USB driver is properly installed, you may now connect the adapter to your trainer board and turn it on.  Invoke the Code Warrior if the trainer board is pre-loaded with Freescale serial monitor, otherwise invoke the AsmIDE.
   

• For using Code Warrior with Freescale serial monitor you need to Download and configure Code Warrior
  http://www.evbplus.com/Code_Warrior_hcs12.html
   

• If the AsmIDE does not communicate with your trainer board then you need to check if the COM port number that is assigned by the AsmIDE matches the USB-to-Serial COM port number that is assigned by Windows' Device Manager. The Device Manager assigns the USB-to-Serial COM port number randomly and it does not know which COM port number that AsmIDE is going to use.
  
  In order to find the USB-to-Serial COM port number that is assigned by Device Manager, you can click through "Control Panel -> Systems -> Hardware -> Device Manager -> Ports".  The USB-to-Serial COM port number will appear (In Windows Vista, you left click on Start, right click on Computer, left click on propriety, then Device Manager and then Continue).
  
  For setting the COM port of the AsmIDE to match that USB-to-Serial COM port number, you can click through "View-> Option->Terminal Window Options" menu, then select the correct COM port from COM1 to COM8.
  

Note:  (This note applies to the Code Warrior IDE as well )

In order to establish a reliable USB communication, always connect the USB adapter to your PC's USB port first before invoking the AsmIDE, otherwise the AsmIDE will not be able to find a COM port.  When ending a debugging session, always close the AsmIDE first before unplugging the USB adapter from your PC's USB port, otherwise the AsmIDE may hang up and you need to re-establish USB communication again. 

As long as you keep the USB adapter connected to your PC's USB port, disconnecting the adapter from your target board will not lose USB communication.

In case the AsmIDE hangs up, you need to close the AsmIDE first, then unplug the USB adapter from your PC's USB port, wait for a few seconds before re-plug in the USB adapter to the USB port, then wait for a few more seconds and allow USB connection to be re-established.  After cycling USB connection you can invoke the AsmIDE again and it may restore the USB communication.  If this does not work, you need to restart your PC, so in order to avoid it, always close the AsmIDE before unplugging the USB adapter from your PC's USB port.

If restarting PC does not solve the problem, you may need to re-install USB driver