Post by thread:[SX]: external program code on a memory chip

Hi, I heard it's possible on certain microcontroller to store the program code on an external memory chip to get some extra space. I would like to know if it's possible with SCENIX's SX28AC chip to get more than 2k of program memory. If it's possible how can I do it, and what kind of memory should I use (any other info could be useful) Thanks -- 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

> I heard it's possible on certain microcontroller to store the program > code on an external memory chip to get some extra space. I would like to > know if it's possible with SCENIX's SX28AC chip to get more than 2k of > program memory. If it's possible how can I do it, and what kind of memory > should I use (any other info could be useful) This doesn't answer you question directly, but some of the 17C PICs can use external program memory. ***************************************************************** Olin Lathrop, embedded systems consultant in Devens Massachusetts (978) 772-3129, spam_OUTolinTakeThisOuTcognivis.com, http://www.cognivis.com -- 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

At 01:34 PM 11/04/2000 -0500, you wrote: >Hi, > I heard it's possible on certain microcontroller to store the program >code on an external memory chip to get some extra space. I would like to >know if it's possible with SCENIX's SX28AC chip to get more than 2k of >program memory. If it's possible how can I do it, and what kind of memory >should I use (any other info could be useful) > No [unless I missed something] -- 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

The SX doesn't support external memory. Some of the PIC17C series do support external memory. The PIC18C architecture is specified to support up to 1MByte of external memory, but, AFAIK, none of the currently avaiable 18C series chips support the external memory. Many PICs do provide internally much more than the 2k of program memory that is available on the SX28. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) {Original Message removed}

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]:"

Pants Systems (contract development of low performance, low function, high-level, high cost software) Seemed funny at the time bob :-)... Sounds like M$ to me... Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

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 .....jamesnewtonKILLspam@spam@sxlist.com SX FAQ: http://www.sxlist.com {Original Message removed}

> 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. That may be because it doesn't come up in search engines and I haven't seen any mention of it other than on this mailing list. Got a link ? Steve. ====================================================== Steve Baldwin Electronic Product Design TLA Microsystems Ltd Microcontroller Specialists PO Box 15-680, New Lynn http://www.tla.co.nz Auckland, New Zealand ph +64 9 820-2221 email: stevebKILLspamtla.co.nz fax +64 9 820-1929 ====================================================== -- 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

Its actually two languages, XPL0 is sort of Pascal like (similar to JAL) but it compiles to a byte code called I2L which is interpreted by the chip. http://www.sxlist.com/languages.htm http://www.sxlist.com/../language/xpl0 Loren Blaney and Richard Ottosen have ported the I2L byte code interpreter to the SX from the original code written for the 6502 by P.J.R. Boyle, Wayne Wall, Ted Dunning, Loren Blaney, Larry Fish and Richard Ottosen. I2L is pretty cool and the license is GPL... There are also ports for the "8080, 6800, PDP-10, IBM-360, a homebrew machine, 65802, 680x0, PIC, Scenix, and the 80x86 family used by the PC" (support for SVGA and mice available for the PC), so you can run a (minimal) XPL0 program (binary) on at least 8 (very) different processors. Its sort of like Java, but GPL'd and not that complex. But that's really not the point. Again, the major advantage that I can see is that you can have a little bit of very fast code doing hardware related things and a bunch of slower code (via external serial flash or FRAM) doing general purpose things. I have a 10-MAR-2000 Version 1.02 copy of the port (it's written for MPASM so could even be used on a large PIC) from Richard and Loren http://www.sxlist.com/xpl0/I2L.ASM I hope that they don't mind that I've posted it at sxlist.com --- James Newton 1-619-652-0593 .....jamesnewtonKILLspam.....sxlist.com SX FAQ: http://www.sxlist.com {Original Message removed}