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BS2 OEM "LITE" Schematics — Parallax Forums

BS2 OEM "LITE" Schematics

Chris SavageChris Savage Parallax EngineeringPosts: 14,406
edited 2015-04-06 14:25 in Robotics
Hello,

·· After several requests from several forum members for schematics of the minimum requirements for a functional OEM BS2 I have compiled the following three schematics which should allow users to integrate a BS2 onto their project without having to have all of the support circuitry.· Essentially these are modified versions of the BS2 OEM schematic which can be found at the following location:

http://www.parallax.com/detail.asp?product_id=27291
NEW LINK

The following files are included inside the ZIP file:

1) OEM BS2.bmp
2) OEM BS2_Lite1.bmp
3) OEM BS2_Lite2.bmp

·· Number·2 is the minimum components required for a functioning OEM BS2 that still includes brownout detection.· If you don't need brownout detection number 3 is the same schematic minus the brownout detector (13811).· Bear in mind that the 13811 is totally optional.· You can even allocate a spot for it in your final product and the BS2 will function whether the 13811 is there or not.· All it really does is attach to Vss, Vdd and the RESET line.· When the voltage falls below around 4.7 volts it pulls the RESET line low.· So you can get by without it, although you may have strange results during power sagging/brownout conditions, including loss of program control.

·· Remember, there is no facility to reprogram the BASIC Stamp in these circuits.· You have three options.· One is to use one of the many RS-232 programming adapters I have seen which would include all the circuitry missing from the original schematic.· Your second option is to reprogram the EEPROM in a standard OEM BS2 and swap the EEPROM out.· I have done this myself.

·· Now for those of you who want to be able to simplifiy the design and still have the ability to program the BS2 in circuit AND make use of the USB port, you use the first schematic, which essentially uses our USB2SER development tool to program the BS2 in-circuit.· This way you do not have anything but a 4-pin header and the bare minimum circuitry required.· When you need to reprogram it will work much like programming an SX in-circuit, through a 4-pin header.· Remember, the 13811 could also be removed if you absolutely had to.

·· I hope some of our forum users are able to make use of these schematics, but now for the fine print...These schematics are not supported by Parallax but are merely provided as a guideline for developing your own stand alone integrated BASIC Stamp applications.· Please do not contact Tech Support for assistance with these.· I am posting them as educational material only!· =)· Enjoy!

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Chris Savage
Parallax Engineering


Post Edited (Chris Savage (Parallax)) : 1/8/2009 7:10:37 PM GMT
zip
zip
OEM BS2.zip
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Comments

  • Steve JoblinSteve Joblin Posts: 784
    edited 2006-01-26 01:14
    Chris... Thanks so much!· Great stuff... I can't believe that this material never existed before!· It has helped me (and I am sure others) out greatly!

    In terms of programming the OEM Stamp-Lite, Chris·indicated that·"You can use one of the many RS-232 programming adapters I have seen which would include all the circuitry missing from the original schematic."· I really don't want to be a pain, but I am having an awful time finding a simple schematic of what one of these RS-232 programming adapters would look like.· I have seen·several of them, but they all seem to work a bit differently.

    HVW Technologies RS-232 Driver Module
    http://www.hvwtech.com/products_view.asp?CatID=163&SubCatID=197&SubSubCatID=198&ProductID=289
    ·
    Kronos Robotics Easy RS232 Interface Kit
    http://www.kronosrobotics.com/xcart/customer/product.php?productid=16167&cat=291&page=1
    ·
    Acroname Serial Interface Connector
    http://www.acroname.com/robotics/parts/S13-SERIAL-INT-CONN.html
    ·
    Pololu Deluxe Serial Adapter Kit
    http://www.pololu.com/products/pololu/0126/
    ·
    AWC RS-I Serial Interface Adapter
    http://www.awce.com/rs1.htm

    How would I know if any of these would work?· Would they work as a "direct connect" our would I still need the 4.7k resistor between Rx and TX?· Would I still need the 1N914 diode on the RX line?· Are these components only needed because of the USM2SER?

    ·Does anyone have a complete schematic (most likely based on a MAX232 or MAX233E) of how to build one that would be able to program the OEM Stamp-Lite?


    Post Edited (Steve Joblin) : 1/26/2006 4:01:02 PM GMT
  • Ryan ClarkeRyan Clarke Posts: 738
    edited 2006-01-26 16:20
    Any RS232 to 5v TTL will work, it's just a matter of a few jumper wires...

    Ryan

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    Ryan Clarke
    Parallax Tech Support

    RClarke@Parallax.com
  • Steve JoblinSteve Joblin Posts: 784
    edited 2006-01-26 16:42
    Would they work as a "direct connect" our would I still need the 4.7k resistor between Rx and TX? Would I still need the 1N914 diode on the RX line? Are these components only needed because of the USM2SER?

    For example, lets say I used Al Williams' AWC RS-I Serial Interface Adapter
    http://www.awce.com/rs1.htm

    There is no schematic for it, but just from the picture it looks like a MAX232 with four caps.· Are you saying that I could hook it up with jumpers without any other components (like the 4.7k resistor between Rx and TX or the 1N914 diode on the RX line?

    Post Edited (Steve Joblin) : 1/26/2006 4:46:30 PM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-01-26 17:17
    Steve,

    ·· What might be better to do is compare the original schematic to the two LITE schematics.· Don't focus on the USB version, those changes are for the USB2SER only at this point.· Any RS-232 circuit you connect to either LITE circuit should be the equivalent of the parts removed from the original circuit.

    ·· One thing to bear in mind is that the SOUT line is driven HIGH, not floating and pulled HIGH as the SIN line is.· What this means is that your circuit should expect that SOUT is driven.· I hope this helps.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Steve JoblinSteve Joblin Posts: 784
    edited 2006-01-26 18:59
    Thanks for being so patient... and I really hope you are not getting totally frustrated with me!!!

    so how would I find an example schematic of an RS232 circuit that would be the equivaqlent of the parts removed from the original circuit? Do you have one?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-01-27 00:30
    Steve,

    ·· Yes, I do have one...The original schematic for a BS2 OEM is linked above.· That schematic shows all the "extra" parts I removed from the schematic to create a LITE version.· You could effectively make a programming dongle for RS-232 using that part of the schematic.· You would just include those parts and then you could plug it in to the LITE schematic (into the SIN and SOUT pins).

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-01-27 18:26
    Oh, one last thought was that you must remember to include the 4.7k resistor that echoes back the data sent from the PC or else the Stamp Editor will not see the BASIC Stamp.· That part usually requires loopback (tying pin 6 and 7 of the serial port together) and echo (the resistor between the RX and TX pins).

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Steve JoblinSteve Joblin Posts: 784
    edited 2006-01-27 18:38
    Thanks... trying to figure out all this based on a MAX232 is getting way too confusing for me (I guess it is not a straight forward as I originally thought). I think my plans are to buy a BS2 OEM, only build the components needed for programming, and build a jumper cable from the OEM to my project board. Was hoping for something a bit more elegant, but at least I know it will work! Again, can't thank you enough for all your help... I really, truly appreciate it!
  • Brian RileyBrian Riley Posts: 626
    edited 2006-04-04 01:53
    I have several of the adapters posted by Steve Joblin above. I have traced them out and the problem with most of them is they implement TxD,RxD, and RTS and/or CTS optionally. None of them seem to implement DTR. The best solution is either a USB2SER , a hand wired MAX232 so you can get the DTR to ATN connections right using a the capacitors, or there is schematic floating around the Propeller chip discussions that shows an RS232 seriai circuit done with 2 2N3904's, a 2N3906, and a few resistors and caps.

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    cheers ... brian riley, n1bq, underhill center, vermont
  • Brian RileyBrian Riley Posts: 626
    edited 2006-04-04 02:02
    Te MN13811, brownout detector, what voltage threshold part was selected 3v, 4.6v, what?

    Tnx .... lot of good info here

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    cheers ... brian riley, n1bq, underhill center, vermont
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-04 02:29
    Hello,

    ·· This should be 4.7 volts, although I haven't looked at the 13811 in some time.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Brian RileyBrian Riley Posts: 626
    edited 2006-04-07 03:14
    Chris Savage (Parallax) said...
    Hello,

    This should be 4.7 volts, although I haven't looked at the 13811 in some time.

    I finally tracked it down to the Parallax document "OEM BS2 BOM.pdf" the MN13811 is a 4.1 volt threshold.

    Thanks for the help. My USB2SER arrived today, off to the workshop tomorrow nad see what I can do.

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    cheers ... brian riley, n1bq, underhill center, vermont
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-01-24 23:06
    Hello everyone,
    ·
    ·· I know the question has come up before about how to connect directly to the interpreter through the serial port using a MAX232 (or similar) Line Driver and there were no previously published articles that I was aware of.· As of today one of our customers has used the schematics in this thread as a guide to perfect this and connect directly to the BS2p40 interpreter chip (SX48).· The following schematic he came up with and wanted to share it with anyone else trying to connect in this manner.· From the customer:
    ·
    Chris,
    ·
    I came up with this design, modified my board and it is successful.· If you want to add this to your zip files I am forwarding this along.· I have been testing code and using the PBasic Stamp Debugger·without any issues.··I appreciated your help and therefore am sending this to help others.·
    ·
    George Calvas (Ford Motor Co.)
    ·
    ·· Bear in mind that the BASIC Stamp requires echo on the RX/TX lines for the Editor to recognize the BASIC Stamp.· In this manner the diode is required due to assertion of the other line across the 4.7K resistor.· George has successfully married this theory on the RS-232 side of the MAX232.· He hopes this helps someone else.· Take care everyone!

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    Chris Savage
    Parallax Tech Support
    bmp
    bmp
    MAX232_OEM.bmp
    999K
  • Steve JoblinSteve Joblin Posts: 784
    edited 2007-01-26 14:48
    Awsome!· I was never able to get it to work... now I have hope!

    Can you just confirm the inputs and outputs... on the left side of the schematic...

    MAX232A Pin·8 goes to Interpeter Serial Port XX
    MAX232A Pin 9 goes to Interpeter Chip·Pin XX
    MAX232A Pin 11 goes to Interpeter Chip·Pin XX
    MAX232A Pin 11 goes to Interpeter Chip·Pin XX

    on the right side of the schematic...

    PB_PC_TX goes to Serial Port Pin XX
    PB_PC_RX goes to Serial Port Pin XX
    The diode goes to ?

    Post Edited (Steve Joblin) : 1/26/2007 3:37:35 PM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-01-26 15:44
    Steve, the interpreter connections are on the left side and the PC connections are on the right side. Take Care.

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    Chris Savage
    Parallax Tech Support
  • Steve JoblinSteve Joblin Posts: 784
    edited 2007-01-26 17:39
    Yes... I realize that... what pins do I connect on the Interpeter side and on the PC side... what is "XX" for each item below?

    MAX232A Pin 8 goes to Interpeter Serial Port XX
    MAX232A Pin 9 goes to Interpeter Chip Pin XX
    MAX232A Pin 11 goes to Interpeter Chip Pin XX
    MAX232A Pin 11 goes to Interpeter Chip Pin XX

    on the right side of the schematic...

    PB_PC_TX goes to Serial Port Pin XX
    PB_PC_RX goes to Serial Port Pin XX


    and what's up with that diode? it's just hanging out there! The diode goes to ?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-01-26 20:32
    Steve,

    I’m sorry; the lines are labeled so I thought you knew where they went from there. That will vary between different interpreter chips as to the exact pin number, but the functional pins are listed same as on the PC side. As for the extra diode, it appears he used some sort of dual-diode package because it was available and is using only one diode from it. You only need the one diode. If I ever have an opportunity to build something using this schematic and known parts and draft a version similar to those posted. For now this, like the others, is as-is information. Take care.

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    Chris Savage
    Parallax Tech Support
  • Steve JoblinSteve Joblin Posts: 784
    edited 2007-01-28 21:51
    Thanks Chris! Appreciate your help! I did try to build it, but with no success [noparse]:([/noparse] Oh well, we both have other things to work on...
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-01-28 23:31
    I will work on this as soon as I get some spare time. Take care.

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    Chris Savage
    Parallax Tech Support
  • polar bear6polar bear6 Posts: 3
    edited 2007-02-02 22:57
    hi, you say that you can only flash this chip once, but if you use a PIC16F57 wouldnt you be able to use it more than once?
  • Steve JoblinSteve Joblin Posts: 784
    edited 2007-02-03 15:11
    Not quite sure I follow Polar bear6... the PIC16F57 is flashed with the Parallax interpreter (it is was turns an ordinary PIC16F57 into the amazing Stamp). This only needs to be done once and you would not want to accidently write over it since you would be loosing what you paid for, so it seems logical that Parallax selected a chip that could only be written once. When you write a program, it is stored on the EEPROM which can be written to hundreds of thousands of times.
  • polar bear6polar bear6 Posts: 3
    edited 2007-02-03 17:55
    okey maybe i was a bit unspesific.
    the schemetic you posted contains the PIC16C57, can i swap that chip with the F version and make a BS2 at home?
    as the cheapass i am i have all the parts i need at hand (yes from old electronics), and i only have a PIC16F57.
    and i really (i mean really) dont want to buy a C version if i can just use the F.
    hope this makes more sense
  • ForrestForrest Posts: 1,341
    edited 2007-02-03 18:14
    Nope, you can't make a Stamp out of an unprogrammed PIC16C57 - unless you happen to work at Parallax. The BS2 Interpreter program is a Parallax's intellectual property - and they don't give it out to anyone. However Parallax will sell you a programmed BS2 Interpreter chip for $11 here www.parallax.com/detail.asp?product_id=PBASIC2C/P or they'll sell you a BS2OEM kit (you solder it together) for $30 here www.parallax.com/detail.asp?product_id=27291
  • polar bear6polar bear6 Posts: 3
    edited 2007-02-03 20:36
    can i extact the BS2 interpreter program from a working BS2? or this ilegal against like parallax ??
  • ForrestForrest Posts: 1,341
    edited 2007-02-03 22:13
    You can try, but I believe it's code protected. As for legality - I have no idea as I'm not a lawyer.
  • Steve JoblinSteve Joblin Posts: 784
    edited 2007-02-03 22:24
    The Interpeter was created by Parallax is their property so you would be making an illegal copy.

    That said, even if you wanted to break the law, you couldn't because you can't extract it... it is burned into the chip.

    The Interpeter is what makes the Stamp a Stamp... think of it as the "secret sauce". It would be like Coke publishing their formula on the internet.

    You can program a PIC yourself using some very inexpensive programmers and free IDE's off the internet... however, none of them enable you to program in BASIC (at least not the free ones).

    Let's take an example... The BASIC STAMP II costs $44... compared to a PIC chip that costs just a few bucks... but you will need a programmer (Let's say you can make one yourself for about $30) and PICBASIC Pro costs $250.

    If you are planning on making products in large quantities, the BASIC Stamp is not cost effective, but for educational, hobby, and small quantity manufacturing, you can't beat it!!
  • FranklinFranklin Posts: 4,747
    edited 2007-02-03 23:40
    YES is illegal against like Parallax !!

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    - Stephen
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-02-05 05:06
    Hello,

    It is not possible to extract the firmware from the chip…You must purchase the chip with the firmware already programmed into it. Take care.

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    Chris Savage
    Parallax Tech Support
  • ECSimsECSims Posts: 19
    edited 2008-01-03 16:41
    Chris and others that have posted to this topic:



    I would like to thank you for your help on setting up this schematic.· It was assembled today, and it worked great with the USB2SER adapter.·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-01-04 15:41
    Thank you. As a note to everyone (in case I didn’t mention it above), you can also use the Prop Plug or Prop Clip in place of the USB2SER. Ideally, in an OEM application the customer would embed the equivalent circuitry of the Prop Plug into the design, eliminating the need for the external device altogether and further reducing cost. I estimate that in quantities of 100 a BS2 with USB interface could be embedded into an OEM design for about $15.00.

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    Chris Savage
    Parallax Tech Support
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