I think there is something to be said for this approach. The XPL0 core language interpreter has been implemented in an SX and the basic stamp (with its' interpreted language) has been very successful. The key advantage of this is that you get A) in ONE chip (or two at the most if you count external program memory) B) a very fast, hardware interface, microcontroller (ala Virtual Peripherals) and C) a slower, more powerful, general purpose computing engine with a big program memory that can be external while still only using a few pins. The problem with the STAMP is that its not configurable. E.g. if I don't need the DTMF but I do need floating point... oh well. The problem with XPL0 is that it is not completely debugged (although it is GPL'd) and people are not showing an interest in it. --- James Newton 1-619-652-0593 mailto:jamesnewton@sxlist.com SX FAQ: http://www.sxlist.com -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Andrew Seddon Sent: Wednesday, November 08, 2000 09:24 To: PICLIST@MITVMA.MIT.EDU Subject: [SX]: external program code on a memory chip I suppose you could write a assembly interpreter. Much like parallax have done with their SX version of the stamp. Except rather than interpreting basic you could use assembly opcodes. I would imagine code running from external mem would work at at least a factor of 15 slower. I suppose tho you could cache a loop etc in the internal SRAM to prehaps make things a tad quicker. I would however recommend that you simply upgrade to a SX52, essentially 2xSX28`s. Andrew Seddon Pants Systems (contract development of low performance, low function, high-level, high cost software) Seemed funny at the time bob :-)... -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" = ONLY! "[EE]:","[OT]:" =her "[BUY]:","[AD]:" -s -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics