In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:

Samuel,

you made an interesting suggestion - it would be pretty easy for SXSim to display the status of the internal program counter - in case I find some more free space in the main window :-) . The IDE Debugger definitely can't do it as the SX device does not allow reading it.

I can't share with you your complaints about the SX design. When the SX was created, the major goal was to design a controller being compatible by some extend to other products already available, plus some enhanced and important new features, like high speed execution with preciely timed, deterministic interrupts, allowing to implement customized peripherals just in software. The SX is not the first controller making use of program memory paging, and variable memory banking. Once you've got the idea, it is pretty easy living with it.

Sorry, I also must disagree with you concerning compound instructions - the SX instruction set does _not_ contain any compound instructions at all. The developers of the assembler have added them for user-convenience. You may think of them as pre-defined macros. Sometimes, compound instructions can cause a lot of problems when placed at the wrong place, e.g. following a skip or conditional skip instruction. It is simply up to you using compound instructions or not - all possible programming tasks can be achieved without using compound instructions at all.

There is no question - other types of controllers/processors but the SX may be better suited for certain applications - you always have the freedom to decide which device you might use but when you decide to go with the SX, you will have to live with its structure and how it must be handled. As you certainly know, the SX is a "frozen" design, so don't expect new enhanced versions with more/other features.

From my point of view, I can only say that I make most of my current income from designing various applications around the SX (from protocol converters up to heavy-duty motor controllers), and I like the SX so much because I can customize it the way I specificly need it, simply in software, without the need seaching the feature lists of other controllers, and then figuring out how to deal with a specific variant of another controller family.

So, we should not complain about what the SX can't do, or might be doing better - let's take and use it as it is, and - most important - we should be glad to know that the SXes are now in the "right hands". Since Parallax has taken over the SX product line, I feel much more comfortable that it will remain viable for a long period of time. A small company like the one I'm running can't spend the time & money to re-designing all its products just because a major part like the SX would no longer be available. This is one of the reasons why I hold the SX-flag high.

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