Apptech wrote: > Is there a reference available that spells this out > clearly enough that a studious beginner can understand it > well and get it right? Yes, the MPASM/MPLIB/MPLINK manual. In this case the chapter "Directive Language". All the directives, including #define, CBLOCK, and RES are individually described in detail. That's where I learned it from. Most of the book is a must-read before writing MPASM code, but this chapter in particular must not be skipped. At the very least you need to read it to understand the general mechanisms MPASM uses and know what's available. Then you go back and look up details as you write code. Anyone who thinks they can save time by not reading it all is being "penny wise and pound foolish". In the end, you're going to spend a lot more time until you will have eventually read it anyway. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist