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Communication issues (not with girlfriend) BS2 serial — Parallax Forums

Communication issues (not with girlfriend) BS2 serial

Turnbull2112Turnbull2112 Posts: 65
edited 2009-02-12 14:05 in BASIC Stamp
I designed a board set up for serial communications with a BS2. I followed the diagram from the Basic Stamp syntax and reference manual that I have attached a photo of as well as the schematic of the serial comms layout I am using. To me, the layout is identical. The problem is that when I power up the·BS2 and connect my serial cable, the stamp stalls. Whatever outputs are high drop out and nothing happens. I am unable to identify the BS2 from the Stamp Editor. Anyone out there have any tricks or ideas??

Thanks for your help,

Rob
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Comments

  • dandreaedandreae Posts: 1,375
    edited 2009-02-03 23:12
    Can you add a schematic of the complete board.· What are you using for a power supply?· Can you take a few voltage measurements on the BASIC stamp?· If so, please measure:

    Vin to Vss =

    Vcc/Vdd to Vss =

    Rst to Vss =

    Sin to Vss =

    Sout to Vss =

    Dave






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    Dave Andreae

    Parallax Tech Support·
  • Turnbull2112Turnbull2112 Posts: 65
    edited 2009-02-04 00:51
    Vin to Vss = 4.577 VDC

    Vcc/Vdd to Vss = 4.989 VDC

    Rst to Vss = 4.987 VDC

    Sin to Vss = .285 VDC

    Sout to Vss = .404 VDC

    Power supply schematic to follow. Thanks for looking!
  • Turnbull2112Turnbull2112 Posts: 65
    edited 2009-02-04 00:52
    Here is the full schematic. Thanks.
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  • dandreaedandreae Posts: 1,375
    edited 2009-02-04 15:15
    Your voltage measurements are off on the "Sin and Sout", they should·read -10v on Sin and -5v on Sout.· This is telling me that there is a problem with the·serial connection.· Please make sure that you are using a straight through serial cable and not a null modem cable.· You can check this by ohming out the cable, making sure that pin 1 goes to pin 1.· Did you add the .1uF capacitors that are shown in the diagram in the BASIC Stamp Manual?

    Dave

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    Dave Andreae

    Parallax Tech Support·
  • stamptrolstamptrol Posts: 1,731
    edited 2009-02-04 20:21
    The other thing to check, especially with a transformer power supply, is that Earth ground is connected where you think it is. It is quite easy to end up shorting out part of the bridge.

    Can you show us the orientation of the diodes in the bridge?

    Or, it may be just as easy to pull the diodes and put a DC supply or batteries on the input to the regulator and try the circuit that way.

    Cheers,

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    Tom Sisk

    http://www.siskconsult.com
    ·
  • Turnbull2112Turnbull2112 Posts: 65
    edited 2009-02-09 23:58
    I have tested this layout with a 9v battery and it runs. I am programming the Stamp on the developement board and transferring it to my project board. Once installed it runs fine but I am unable to connect to it with the serial cable. I am using the .1uf capacitors. I didnt have my serial cable attached when I took the above voltage measurements. Should I have had it connected? Thanks again guys.
  • JWTrJWTr Posts: 5
    edited 2009-02-10 19:52
    I have a similar problem, I cannot program my design with my PC but I CAN program my design with the Stache programmer

    Vin to Vss = 5.2v

    Vcc/Vdd to Vss = 4.8

    Rst to Vss = 4.8

    Sin to Vss = 0

    Sout to Vss =0

    this is taken while in normal operation Not trying to program.

    I have tried shorting the cap on the ATN line, and about everything I can think of, any input will help

    Dave
  • dandreaedandreae Posts: 1,375
    edited 2009-02-10 23:24
    Turnbull2112 said...
    I have tested this layout with a 9v battery and it runs. I am programming the Stamp on the developement board and transferring it to my project board. Once installed it runs fine but I am unable to connect to it with the serial cable. I am using the .1uf capacitors. I didnt have my serial cable attached when I took the above voltage measurements. Should I have had it connected? Thanks again guys.
    Yes, you need the cable connected in order to take the measurements.

    Regards,

    Dave

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    Dave Andreae

    Parallax Tech Support·
  • dandreaedandreae Posts: 1,375
    edited 2009-02-10 23:26
    JWTr said...
    I have a similar problem, I cannot program my design with my PC but I CAN program my design with the Stache programmer

    Vin to Vss = 5.2v

    Vcc/Vdd to Vss = 4.8

    Rst to Vss = 4.8

    Sin to Vss = 0

    Sout to Vss =0

    this is taken while in normal operation Not trying to program.

    I have tried shorting the cap on the ATN line, and about everything I can think of, any input will help

    Dave
    Make sure that you do not have any other software running that uses a serial port or it will block the stamp editor.· Make sure your serila cable is a straight cable and not a null modem cable.
    Regards,
    Dave

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dave Andreae

    Parallax Tech Support·
  • JWTrJWTr Posts: 5
    edited 2009-02-11 13:45
    I use the PC to program the stache back to back with a failure, there is something missing in the schematic or description of how to layout this com. I have followed the schematics to the T I have verified and re verified,

    I've laid the board out 2 times the second time cutting trace length and widening traces

    Does the reset need tied low or high during programing?
    what esle is there,

    I have traces exactly as show,

    I'm using Ceramic caps do I need to change to Tant's or something,

    Is there someone I can call and talk to for a few minutes,

    guys I have 4 different products coming out with stamps in them while volume is low were still talking a total of over 200 stamps lcd's pwmpal's

    If I can't figure this out I'm switching to another product.
  • dandreaedandreae Posts: 1,375
    edited 2009-02-11 15:23
    The reset needs to be tied high. You can call us at 1-888-997-8267.· Did you follow the schematic on page 28 of the BASIC Stamp manual?· If so, this telling me that there maybe a different issue.

    Regards,

    Dave

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    Dave Andreae

    Parallax Tech Support·
  • JWTrJWTr Posts: 5
    edited 2009-02-12 14:05
    I got it working by changing the design,

    My original design include 2 caps as in the design of the super carrier board. I was using the exact design that is show in the parallax documentation for the super carrier board,

    I changed it to a straight through design illustrated in the Stamp manual. Page 27 of the Basic stamp programming manual 2.0

    I shouldn't write messages when I'm frustrated beyond reason. but I would really like to know why the design of the Supercarrier board is wrong.

    Another major anomaly is that the portable field programmer will program the boards with this design while my PC won't BUT my PC will program the Super carrier boards.

    I cannot understand why there is these differences in design and why the portable programmer programs it while the PC won't When I had the differnce between the 2 programmers it really frustrated me
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