External memory for spin code

richaj45

Hello:

If an external serial RAM chip was attached to the prop, and if the driver was available, then is it possible for the spin interpreter to process byte codes form that external RAM?

If so then spin programs could be very large indeed.

Thanks for your time.
rich

Dave Hein

The ROM Spin interpreter can't execute byte codes from external RAM. It would be possible to write a Spin interpreter that could do this, but nobody has done it yet.

Duane Degn

Rich,

Have you seen this thread?

I'd think it wouldn't be too hard to modify Dave Hein's cool (understatement) program to read the binary objects from an external RAM chip. You'd need a way to load the binary onto the chip though (not trivial but real hard either).

jazzed

Right, Spin can't execute external memory code directly. More over, it can't read code or data size greater than 64KB.

Duane's suggestion is best.

Dave Hein

An then there was this thread. Yes, Big Spin is still a pipedream, but somebody might do it eventually on P1. It will most likely become a reality on P2.

jazzed

Dave Hein wrote: »

An then there was this thread. Yes, Big Spin is still a pipedream, but somebody might do it eventually on P1. It will most likely become a reality on P2.

LOL. I totally forgot about that. Some demos were posted here: http://forums.parallax.com/showthread.php/128921-Big-Spin-is-it-still-a-pipedream?p=976896&viewfull=1#post976896

@Dave, Having an object loader that works is great.

Dr_Acula

To add to Duane's link, post #34 http://forums.parallax.com/showthread.php/153351-Overlays-for-large-spin-programs/page2 is the code Dave Hein wrote.

This works!

Precompile parts of your spin program and save the binary files on an SD card and then load them in as needed. The code could also be stored in Flash or any external ram.

I'm working through the process of splitting a typical object into two parts - the pasm part which can be preloaded and moved into a cog, and then the resident driver part. I'll write it up when I get it finished. Every object that has cog pasm code could be rewritten in this way to save 2k of hub ram each time.