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development board for SX20? — Parallax Forums

development board for SX20?

guymatzguymatz Posts: 5
edited 2005-05-01 19:44 in General Discussion
hey,
i just got a new "SX Tech Tool Kit PLUS" and included some sx20 chips in the order thinking that they're cheap enough to actually use. the trouble is i can't seem to figure out how to develop for the little buggers! i've tried hammering one into the SX tech board but it just didn't feel right. wink.gif

any advice is appreciated!

thanks,
guy

Comments

  • KenMKenM Posts: 657
    edited 2005-04-27 03:19
    What?
  • kb2hapkb2hap Posts: 218
    edited 2005-04-27 11:47
    The toolkit plus come with SX28's that fit good in the board. you'd have to get an adapter for the 20's

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  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-04-27 14:01
    Did you accidently get some (DIP) SX18s? They're not in production anymore, and have been replaced by the (SSOP) SX20.· We will be producing an inexpensive dev board for the SX20 -- the board will come with the SX20 soldered to it so you don't have to.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • KenMKenM Posts: 657
    edited 2005-04-27 23:55
    Jon Williams said...
    We will be producing an inexpensive dev board for the SX20 -- the board will come with the SX20 soldered to it so you don't have to.

    When when when when?????? Based on the sneak prevues severals months back, can't wait to get my hands on one.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-04-28 00:43
    You did not see the SX20 board "several months back" -- that was the SX48 and SX52 board which we did first to support SX/B 1.2 (and that there's no DIP version of those parts). The SX20 and SX28 versions of those boards came next, and I have seen them with my own eyes. That said, I don't know when they will ship.

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    Jon Williams
    Applications Engineer, Parallax
    Dallas, TX· USA
  • Ken GraceyKen Gracey Posts: 7,401
    edited 2005-04-28 04:40
    Jon and Ken:

    I checked tonight and the SX48/52 board is expected to arrive at Parallax on June 20th. And as planned, they will be about $10.00 each (with the SX chip and a few other components for power supply, SX-Key header, resonator).

    Lead times for anything we build outside of the office are really long right now.

    Ken Gracey
    Parallax, Inc.
  • KenMKenM Posts: 657
    edited 2005-04-28 13:41
    Ken,

    Thank you for the update.

    K
  • guymatzguymatz Posts: 5
    edited 2005-04-28 14:21
    Jon Williams said...
    Did you accidently get some (DIP) SX18s? They're not in production anymore, and have been replaced by the (SSOP) SX20. We will be producing an inexpensive dev board for the SX20 -- the board will come with the SX20 soldered to it so you don't have to.

    i *DID* get the SX18 DPs . . . is there anything i can do with them!? i'm trying to build a **very** simple remote control . . .

    thanks a lot!
    guy
  • kb2hapkb2hap Posts: 218
    edited 2005-04-28 14:27
    Well you can still use the SX-18 but you will either have to make you own programming board or make an adapter to fit the SX tech board either way is very simple to do and takes minimal basic parts. There is a schematic in the SX-Key book which explains how to hook it up.

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  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-04-28 16:17
    Be sure to minimize the lead lengths of the OSC1 and OSC2 connections, these particular connections are sensitive to parasitic capacitance caused by long wire lengths, especially when using the resonator (but the SX-Key will have problems as well).
  • guymatzguymatz Posts: 5
    edited 2005-04-28 16:26
    hmmm . . . i wish i had any idea what you just said. smile.gif
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-04-28 16:44
    Sorry for that, let me try again. The distance between the oscillator and the SX-18 needs to be kept as short as possible (when programming the SX the SX-Key acts as the oscillator, when the SX has already been programmed the resonator is the oscillator (the three pinned blue part that plugs into the three holed socket on the SX-tech board). If either of these are too far away from the SX you will experience problems. In a nutshell if you stick the SX-18 in a breadboard, put the header you plug the SX-Key into close to the SX.

    Does this explanation make more sense to you?
  • guymatzguymatz Posts: 5
    edited 2005-04-28 18:21
    no . . . i'm really new at this stuff. if anyone has any starting points for me, please post, howver that may be for a different thread . . .
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-04-28 18:52
    Ok you said you have the SX-tech board lite. Look at the board, see the four pin header that says "Vdd Osc1 Osc2 Gnd" on the board underneath it? That is where you plug in the SX-Key to program the chip. Now look at the 3 hole socket near there, this is where the resonator is plugged into (the 3 pin blue part, you got two of them in your kit, a 50Mhz and 4Mhz). Now look at the trace on the board that connects both of these to the SX, see how it about 1 inch in length? If that length was much greater, problems will occur. To program an SX18 you will have to replicate at a bare minimum the 4-pin header so you can plug the SX-Key into. When you do this you cannot stick the SX18 in one corner of the breadboard and the 4-pin header in the opposite corner of the breadboard. They need to be physically close to each other.

    Since you are new I would put off trying to figure out how to program the SX-18 until you become more experienced. You should have gotten 2 SX28s with your SX-tech board lite, is there a reason you absolutely need to use the SX18 instead?

    You may want to read "Whats a Microcontroller" its written for a basic stamp user but it covers things which apply to the SX as well.
    A free copy is availible here.

    Considering your newness, you should seriously consider getting Guenther Daubach's book "Programming the SX Microcontroller: A Complete Guide"·you will not regret the investment. You should also read through Al Williams "Beginning Assembly Language for the SX Microcontroller"· which is availible for free downloading.

    Post Edited (Paul Baker) : 4/28/2005 7:05:54 PM GMT
  • David BDavid B Posts: 592
    edited 2005-04-28 18:57
    When I first started making my own Scenix programming boards, I had the bright idea of having one board with one header connector for the Sx-Key programmer and two ZIF sockets, one for sx18 and one for sx28, with the SX-Key header pins connecting through a toggle switch to whichever socket I was using.

    Nope! It didn't work. Those few inches of wire routed through that toggle switch was all it took to cause the programmer/oscillators to fail.

    What I learned really is pretty straightforward - you just mount your Sx chip oscillator pins as close as you can to your Sx-Key pins. I've been using about an inch separation, which seems to work well. Or you can experiment on your own - try to program a chip using longer and longer connection wires, until your programming fails. It'll be a good way to get some practical experience!

    David
  • KenMKenM Posts: 657
    edited 2005-04-30 01:13
    Believe it or not, I have never had a problem programming my SX with this cluge of wires that are about 12 inches long.
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  • pjvpjv Posts: 1,903
    edited 2005-04-30 04:39
    Not even at high speeds???

    Peter (pjv)
  • BongoBongo Posts: 65
    edited 2005-04-30 05:30
    Amazing.· But I am curious.· Why not include a 4 pin sil header for the key in your design?
    And were is Loser?· I miss his enthusiasm.

    Bongo
  • KenMKenM Posts: 657
    edited 2005-04-30 15:43
    The post was in response to David B "try to program a chip using longer and longer connection wires"

    I only programmed the SX in the manner shown, never tried to run it like that.

    Peter, you mentioned "not even at high speeds?" Does the user have control over the programming speed? If so I was unaware of that.

    Regarding a 4p sil, nowadays I do include one.

    Curious, do any of you incorporate a ground plane at the resonator? That was a suggestion from I think James Newton, and or Ubicom docs.

    Ken

    Post Edited (KenM) : 4/30/2005 3:46:37 PM GMT
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  • pjvpjv Posts: 1,903
    edited 2005-04-30 21:44
    Hi Ken;

    No, my reference was to RUNning the program using the SXKey as the clock source. Longer lines are not an issue for programming the device; that happens at a clock rate of about 2400 Hz if I recall correctly. During programming, the SX chip uses its internal 4Mhz oscillator to communicate via serial bit-bangging with the SXKey.

    I could see long lines being a problem for the SXKey at over 50Mhz though.

    I don't use ground planes near the oscillator/resonator circuitry, but its a good idea if you can manage it. Should make EMI slightly less.

    Peter (pjv)
  • BongoBongo Posts: 65
    edited 2005-05-01 07:57
    Re: Ground Plane for the xtal,· I always use one.· More an excercise in good board design than a proven benefit, for me.· I created a 3 legged footprint for my design software, and tie one leg to ground on the schematic.· The xtal wires are bent so the xtal can lie flat on the board, with a wire soldered onto the case at the top, to ground on the board, with some copper left intact on the top layer under the xtal case.

    Have used for everything, from the small round 32.768khz to the square numbers.

    Boards can be designed for low emi, which is usually a better idea than having to shield around sensitive areas, if they are to be implimented.

    From memory, there are some easy to follow guidelines out there somewhere.................



    bongo
  • guymatzguymatz Posts: 5
    edited 2005-05-01 19:44
    wow, you guys really get off-topic! smile.gif
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