Hi all i am using ISD feature of keil for debugging small routine.ISD was communicating with target on board and was debugging properly,but as i added some more code which was not using any of resources of ISD,i got message "'?ISD?READXMEM?' is missing. please make sure ISD51 application is linked to your application " i could not find any problem with the code that was added later. can anybody guide me where problem might be ? Regards Naresh Rana