Although I have been working as a programmer for the last 20 years or so, I am now to microcontrollers and robots. Over the last several weeks I have acquired a number of books, some of which specify PIC controllers. Are there any listings or rules of thumb for replacing the PIC with an SX.

First of all what are you doing?

Listings or Rules of Thumbs?

www.sxlist.com also has www.piclist.com   You can compare the two in depth.

There is also PIC to SX / SX to PIC at www.semis.demon.co.uk/SX/SXtoPIC.html
I think that you will find several facts are significant.

1.  You must buy a C compiler for PIC programming. It is not free.  Neither is Basic.  Only their Assembly language is free.  The SX has SX/B and SASM provided for free.
2.  PIC documentation is vast and covers a diverse universe of products with differenet Mnemonics for different generations.  And different architectues related to different sizes.  SX documentation is a smaller, but still quite useful universe.
3.  A free or low cost programer doesn't really offest the costs of additional software tools and books.

4.  The SX is in some cases pin compatible with the PIC, but you do have to be specific about which one.  Currently, only the 28pin DIP is available in the SX.  The SX-48 comes in a surface mount package or Proto Board.
5.  Sx Assembler is a much more consistent language within all its products.  Differences are mainly related to additional ports, additional timers, and more memory.  Generally you have only two architectures to choose between, not hundreds.
6.  Due to the higher speed, the SX is able to produce peripherials in software and allows more flexiblity and compactness of design.  [You don't have to buy a chip with extra features just to get the features you need].

7.  SX Assembly Mnemonics are more intuitiive, more consistent, and easier to use.  PIC Assembly Mnemonics are a bit harder to read than SX because direction word moves can in some cases be altered by an additonal direction variable.  So MoveWF may go from f to w or from w to f.   At times, it is hard to sort all this out and you must be careful [read and double check with a reference at the same time].

PIC is very attractive as it seems that you can just buy a DIP and muddle through it very cheaply.  But you are indeed muddling.  Eventually costs will become a barrier The SX provides a more supportive, more direct solution that will take you further for one purchase [the Development board with programmer and texts].

Of course you can buy the SX-Blitz and a few chips and muddle along in a similar fashion to the PIC, but I presume that you want to learn the product fully.

Thanks Kramer,
Just the sort of thing I was looking for. I will stick with Parallax and the SX chips and muddle thru any translation problems.

Let's not forget Guenther's SXSim. This is invaluble for debugging without hardware.
Bean.

One of the sites I mentioned has a 'translation/comparison spread sheet' that I am using to convert PIC code to SX.  
It really is just for one type [the 16C5X series] and obviously there are some omissions, but it is a good start.

Sadly, my printout doesn't have the Address on it, so I have lost the source.

There is a lot of code that can be converted over.  Some is on robotics sites [e.g., Seattle Robotics]  PIClist offers a wealth of transferible information.

Going from PIC to SX is much easier as the relationship is NOT one-to-one, but MANY-to-one in that direction.  I just noticed that BasicAtom has have bare PIC project boards that can be use with the SX-18 and provide MAX-232 and DB9 on board.  I am not sure if the SX-28 is compatible with their other one [that uses 28 pins/40pins], but it is worth some reading up on.

at sxlist.com
http://www.sxlist.com/cgi-bin/mpasm2sasm2.exe converts PIC code to SX code.