Converting from BS2 to BS2sx

Chicago Mike

So one of my projects has grown too big for my original BS2, so I went and bought a BS2sx, because I needed more programming space. I was at the limit, literally with code length. I changed the compiler directive, and according to the memory map after rerunning, I have no more room? I added a few lines of code and I'm still out of room? What am I doing wrong here?

Mike Green

All of the Parallax Stamp processors use a bank structure for expanding the program space. You don't just get the ability to have a bigger monolithic program. You actually have to partition your program into separate programs, each with no more than 2K. The separate programs can have common information in that they share the variables and scratch RAM in the "bigger" processors, but subroutines have to be duplicated in each "bank" where they are used, so it's not simple. You compile the "banks" as separate pieces of a project and the Stamp Editor will load them all or individually into your BS2sx. Look at the RUN command for details and examples.

Gadgetman

There's a few gotcha's you should be aware of, like the variable map.

You only have one set of variables, but you'll need to define them in all the programs, and this must be done so that they end up in the same place, too.
I suggest that you read Nuts&Volts column 87: Multibank programming

Edit: I forgot that the BS2sx had scratchpad RAM, and that is of course the recommended way of passing variables.

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Post Edited (Gadgetman) : 3/18/2006 9:34:10 PM GMT