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Schematic for BS2P24/40 Demo Board — Parallax Forums

Schematic for BS2P24/40 Demo Board

basicstampedebasicstampede Posts: 214
edited 2006-12-07 17:48 in BASIC Stamp
Hello,

1.· Where can I find schematic of BS2P24/40 Demo Board?· I cannot find·it in·Parallax website anymore.

2.· I was trying out N & V Column 124 (Fig. 124.1 for standard RC Time).· I used my BS2p24/40 board, and connected the board's A15 (instead of P15).· I was surprised that it worked since I use BS2p24 (not 40).
I thought A15 was for the auxiliary ports for BS2p40 only.
Should A15 on the board·be connected to P15 of BS2p24?

3.· Then, I tried the next example Fig. 124.3 and used A1, A2, A3 (instead of P1, P2, P3).· Nothing worked.· Then I tried P1, P2, P3.· Nothing worked.· Any idea why?

My BS2P24 is working, because when I tried the circuit on another board, everything works as expected.

Thanks.

·

Comments

  • basicstampedebasicstampede Posts: 214
    edited 2006-12-07 16:56
    Some update...

    I find that if I download my program, then unplug the RS232 cable and then press Reset button on the board, it seems to work.·
    i.e. while the RS232 is connected from board to PC,·my program·is prevented from running.

    Does anyone concur this is how it SHOULD operate?

    If yes, why did Parallax design it such·way?· (It is much more·of a hassle to have to unplug RS232 after every download).·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-12-07 16:57
    Hello,
    ·
    ·· On the BS2p24/40 Demo Board the socket handles a 40 pin chip.· If you look at the layout for that it means that when a 40 pin module is plugged in everything is as labeled.· However, if you plug in a 24 pin module P8 through P15 will now be plugged into where A8 through A15 are on the 40 pin module.· Of course, P8 through P15 and A0 through A7 are unoccupied at this point.· In any event I have linked the web page which has the schematic on it.· I hope this helps.· Take care.

    http://www.parallax.com/detail.asp?product_id=45187

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    Chris Savage
    Parallax Tech Support
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-12-07 17:08
    Hello,
    ·
    ·· That is not the desired operation…It sounds like your PC may be manipulating the DTR line when the cable is connected, constantly resetting the BASIC Stamp.· Are you able to test the RESET line for logic level?· A DMM/VOM won’t be much help here.

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    Chris Savage
    Parallax Tech Support
  • basicstampedebasicstampede Posts: 214
    edited 2006-12-07 17:09
    Chris,

    Thanks for the link.· The document does help.· However, what about the question about program not executing if RS232 cable is connected?

    Thanks.
  • basicstampedebasicstampede Posts: 214
    edited 2006-12-07 17:17
    Chris,

    Thanks for explanation of X4 and X5 connectors.

    For Connector X1, do P0 through P15 correspond to Stamp's P0 to P15 regardless of whether 24 or 40 pin version is used?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-12-07 17:36
    Hello,
    ·
    ·· The X4 connector is P0 through P15 and the X5 connector is A0 through A15 on a BS2p40.· If you put a 24 pin module in then you would use P0 through P7 on X4 and A8 through A15 on X5.· I answered your other question a few posts up.· Take care.

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    Chris Savage
    Parallax Tech Support
  • basicstampedebasicstampede Posts: 214
    edited 2006-12-07 17:43
    Thanks for your help.· I got a new laptop and I think it is behind all these problems.

    Just now, I tried using my NX1000 board.· Even though it it properly connected & powered, I cannot even download a program.· It says Stamp not found!

    Any idea if I can·fix·this by changing some setting on my PC?

    By the way, it appears that P0 to P15 on X1 are same as P0·to P15 on X4.
  • basicstampedebasicstampede Posts: 214
    edited 2006-12-07 17:47
    Big oops.· I connected it to the other RS232 connector on NX1000...that's why it didn't work.

    Anyway, after connecting it to the proper connector, I can download, but have the same problem on NX1000 as in 24/40 Demo board.· That is, program will run only if I unplug the RS232 and press Reset button.

    Is there an easy way to make my new PC's RS232 behave like my old PC?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-12-07 17:48
    The X1 header should be the same as above…It should only work that way if you’re using a BS2p40.· With a 24-pin module I don’t believe you can access P8 through P15.· As for the NX-1000 problem I would recommend a new thread for that.· Take care.

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    Chris Savage
    Parallax Tech Support
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