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Serial Interface "Key" for BS2 — Parallax Forums

Serial Interface "Key" for BS2

Steve JoblinSteve Joblin Posts: 784
edited 2005-11-01 21:40 in BASIC Stamp
Does anyone know of an existing circuit board that has all of the Serial Interface components that interface to the Stamp 2 Interpreter Chip.· I would like my project to only have the Interpreter Chip, EEPROM, and Resonator (and a capacitor).· I would like to have all of the Serial Interfacing components on a "Key" that would plug in via .1" posts (like the SX-Key).

This will provide a cost savings over the long term, since I can buy the Interpreter, EEPROM and Resonator for $20 compared to the OEM price of $45 (yes, I know that there is currently a special on OEM's for $30 now).· I will likely buy an OEM to get the components and "first set" of Interpreter, EEPROM and Resonator.· Then it will be a $10 savings each time I do a Stamp project. (or $25 savings if they are no·longer on sale).

I do not consider the votage regulator as part of the Stamp since I am considering the voltage regulator as part of the rest of the project cost.

I can't easily prototype my own since the DB-9 connector does not fit into standard .1 spacing on a typical protoboard.

Any ideas?·

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-10-31 17:08
    You don't have to buy the parts (other than our interpreter), but you'd be safe in using our schematic -- it's avaiable as a free download.

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    Jon Williams
    Applications Engineer, Parallax
  • Steve JoblinSteve Joblin Posts: 784
    edited 2005-10-31 18:25
    Thanks John - I was looking for something that was a kit or premade board so it looks nice.. Does such a thing exist or do I have to scratch build it?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-10-31 19:17
    Steve,

    ·· What about USB2SER?

    http://www.parallax.com/detail.asp?product_id=28024

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-10-31 19:35
    Steve,

    You might consider using a tool like ExpressPCB to make the custom board. If you can fit it onto their standard board size you can get three for $51 -- I think this is a deal versus point-to-point wiring. Check them out: www.expresspcb.com. BTW...if you do go the ExpressPCB route, be sure you start with a schematic; once it checks out the PCB layout program will help you connect one component to another.

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    Jon Williams
    Applications Engineer, Parallax
  • Steve JoblinSteve Joblin Posts: 784
    edited 2005-10-31 20:38
    Chris - This is exactly what I was looking for! Figures with my luck it is backordered! Does anyone make something like this that is "PC Serial-to-Stamp Serial" vs "USB-to-Stamp Serial (like the USB2SER)? The laptop I use for my Stamping does not have a USB port.

    Jon - have you had any experience with Sparkfun's Circuit Board services? http://www.sparkfun.com/shop/index.php?shop=1&cart=449123&cat=86& at $5/sq in, it will only cost me $10.00 at most!
  • Robert KubichekRobert Kubichek Posts: 343
    edited 2005-10-31 21:09
    Steve Joblin said...
    Thanks John - I was looking for something that was a kit or premade board so it looks nice.. Does such a thing exist or do I have to scratch build it?



    Have you tried this site the price is quite reasonable for DTE/DCE RS232/TTL cards...

    www.hvwtech.com/products_list.asp?CatID=163&SubCatID=197&SubSubCatID=198

    Bob N9LVU scool.gif
  • Steve JoblinSteve Joblin Posts: 784
    edited 2005-10-31 21:36
    Robert - Thanks for the find... I actually have purchased a few things at HVW over the years.. Great company!

    This is exactly what I was thinking about! Which one do I buy to connect my PC Serial port to the Stamp Interpreter chip? The DTE or the DCE? I will ask HVW as well, but wondered if you had any specific experience with this.
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-10-31 22:00
    www.kronosrobotics.com also has a nice RS-232 to TTL adapter.

    You probably want the DCE version, with sockets (aka female), as this will let you plug your PC into the adapter with a 'straight through' RS-232 cable. Note on your module you'll have to 'loop' pin 6 to pin 7.

    Note you'll have to connect DTR through the module to the 'ATN' signal of the PIC in order to reset it for programming. I'm not sure what the circuit should be there -- look at the schematic of the BOE or OEM for more pointers.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-10-31 22:18
    There are somethings to keep in mind here -- the editor counts on characters being echoed back through the RS-232 interface on the BASIC Stamp; if no Stamp, no echo, and if you don't provide that mechanism in the solution you select you may not be able to program your module. I suggest you download our programming protocol docs and read through them; if you know what the editor does and is expecting you can select an interface accordingly.

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    Jon Williams
    Applications Engineer, Parallax
  • Steve JoblinSteve Joblin Posts: 784
    edited 2005-11-01 14:46
    Jon - Devil is in the details... although you would think that HVW Technologies solution would work, I confirmed with them that it will not! I doubt that Kronosrobotics solution will work since they are trying to market their own Micon. Looks like I will need to go the custom development route. Again, thanks for filling me in on the details!
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-11-01 16:55
    Yes, Kronos is trying to market their own custom implementation. That doesn't mean their RS232 to TTL converter requires their custom implementation. I think it has enough 'hooks' to do what you want, but you have to confirm that yourself.
  • ForrestForrest Posts: 1,341
    edited 2005-11-01 17:42
    Here's a simple RS232 shifter board that uses transistors instead of a MAX232 chip, it's inexpensive ($4.95) and sold in kit form so you can easily swap a component if necessary to change the design. It's sold by www.sparkfun.com - just search for PType-Shifter
  • CJCJ Posts: 470
    edited 2005-11-01 21:18
    wouldn't the BS2 OEM schematic be a good starting point?
  • Steve JoblinSteve Joblin Posts: 784
    edited 2005-11-01 21:40
    CJ - yes... I was trying to create just the "front end" serial interface portion of the BS2 OEM. I was hoping that someone had a pre-existing circuit board with just the "front end" serial interface portion. Looks like I will build my own by buying an OEM and just mounting the components that I need.
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