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- Hardware Communication Eailure- Sheck serial connection and power supply. err — Parallax Forums

- Hardware Communication Eailure- Sheck serial connection and power supply. err

MrdavidjenkinsMrdavidjenkins Posts: 49
edited 2005-07-29 16:08 in BASIC Stamp
I started getting this error on some of the OEM basic 2 stamps that I have been working with.· I bought a couple of the BASIC Interpreter chips for $11 to see if they would be a quick, cheap fix.· No luck, I get the same error.

Does anyone have any thoughts on how to fix this?

The PC identifies the chip correctly and that different power supplies do not appear to help.


Thanks for· reading this.

Comments

  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-22 22:02
    have you verified VDD 4.98 Vdc under load? Frequently· a sagging power supply can cause problems.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-07-22 22:12
    David,

    ·· This could be something in the programming circuitry then, if not the interpreter.· There are a few components related to that on the OEM boards.· Of course, I should ask you, are you using a laptop or USB converter?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-22 22:36
    I am using a desktop with a serial cable. Units work great out of the box. I get 5.02 volts on the VDD / VSS. I put a 470 ohm resistor on the VDD and get a 5.01 volts. I use a rechargable 9v battery as the power source and have put in a alkalyne battery to see if that helped. It did not.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-07-22 23:12
    David,

    ·· I would really consider trying another power source, such as a wall adapter rated at least 300mA.· Can't hurt, right?· Also, what is connected to the pins (Any/All) while this is happening?· You aren't tying the RES line high are you?


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com


    Post Edited (Chris Savage (Parallax)) : 7/22/2005 11:50:01 PM GMT
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-22 23:41
    Okay - I will try that.· Everyone have a good weekend.

    ·
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-24 03:22
    I set up a breadboard with a sceptr 9 v 300ma transformer. No luck - the editor reports a Basic Stamp 2, correctly, but still gives me the Hardware Communication Eailure- Sheck serial connection and power supply. error Message. Any ideas or suggestions will be appreciated.

    Thanks
  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-24 03:32
    I have had problems where comm ports ( interrupts) get buggered as a result of adding / removing peripherals. Leave the Stamp powered up, reboot and see if the OS can "find" it.
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-24 13:14
    This is a neat idea. I will try. I also have an old win 98 desktop machine that I will try with the stamp. Thanks for the suggestion, Phil.
  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-24 14:57
    any luck yet?
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-24 15:12
    I tried the bootup and hooking it up to a second machine. Unfortunately, same error as before. Appreciate your idea, though. It was a good one.
  • ForrestForrest Posts: 1,341
    edited 2005-07-24 16:27
    Uninstall any PDA Hotsync software you have installed on the computer and retry.
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-24 16:34
    Will do. Sounds like a good idea.
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-24 16:46
    I tried your suggestion about taking the activesync off. I did so then rebooted the machine. I still got the same error. I will pick up a new rs232 cable today to see if that might be the problem.
    Again, appreciate everones thoughts on this. If I get an answer to this, I will summarize and post it for the next guy.
  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-24 17:11
    If they ever worked, then it is safe to assume they are built correctly. The EEprom can "worn out" after some astronomically large number of read/write cycles. Probably not an issue. Are you absolutely positive the serial port is properly identified and it is functioning? If not disconnect your stamp from the serial port. Start up hyperterm. Select the same com port you are using for your STAMP. Go to the ASCII setup and turn Echo Off. Jumper pins 2 and 3 on the serial cable, If the character you typed shows up on the screen, then it is being seen through your jumper and the port is working. Remove the jumper and the char should not be echoed to the screen. Do this to make certain the character is being seen through the jumper.

    My next step would be to take an o'scope and look at the data going to / from the stamp. But I'm guessing you don't have an o'scope.
    Here is alink to the BS2 OEM schematic. http://www.parallax.com/dl/docs/prod/schem/bs2oem.pdf
    There is not a lot of hardware. Always do the simple stuff first. Power it up with a ammeter in series with the power supply. Watch it for a few minutes if the current starts to creep up, or jumps suddenly, it's a sign of a defective part cooking on its way to ground. Feel or sniff the parts on the board, for heat ( your nose is surprisingly sensitive to temp changes). Nothing should be warm. Q1, Q2, and Q3 can be checked with an ohm meter preferably in the diode check mode. Or just replace them for a few bucks. The four compnents Q1,2&3 and U3 translate the +/- 12 v RS232 at the PC to 0 and +5 volt RS232 used at the stamp. Q1and 2 are 2n3904 and Q3 is a 2n3906. All of which I believe are available at Radio Shack. Check online, you can even check if a store near you has it in stock. I am mystified by U3's function but it could easily be determined by googling it. Lastly, if you're convinced these are dead boards, I might be interested in buying them for cheap.
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-28 13:12
    Thanks for the great ideas.·· They are a little advanced for my skills.I will consider your offer to buy these OEM from me.· However, I tried a couple of new things that I want to post first.

    I bought a new serial cable, uninstalled activesync and tested them again. 4 of the 5 identified the bs2, but I got the same Hardware communication failure error.··VOltages look good.

    Anyway, I have·just·tried these on 2 different rebooted·desktops with 2 different cables and removed activesync from both of the desktops.· I am using a ac transformer now instead of a 9 volt battery.··Can anyone suggest any other ideas?

    Any idea if it would be cost effective to have Parallax diagnoise and fix them?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-07-28 14:17
    David,

    ·· I'm sure something could be worked out, but if a new serial cable made such a difference, my next question would be, is there any way you can test these on another computer?· If you decide to go with having us check them out, contact me directly at Tech Support and I will see what I can do for you.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-28 15:55
    Okay, Thanks!
  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-28 23:14
    I believe the Identification of the port is accomplised by a jumper on the BS2 serial connector from pin 6 to 7. 1) do you have Hyperterminal on your machine? Have you communicated with ANYTHING connected to the serial port in queston?
  • MrdavidjenkinsMrdavidjenkins Posts: 49
    edited 2005-07-29 12:37
    I appreciate the help, and I will check what you suggest. Odd thing is, I have used 2 diferent desktops wit the basic 2 stamps and both desktops gave me the same results.
    Thanks
  • Philip GamblinPhilip Gamblin Posts: 202
    edited 2005-07-29 16:08
    I am still unclear. Did you build these or did you purchase them assembled ? If you built them, look closely at the row of transistors and verify thath their packsge outlines match the silkscreen. Did the Stamps in question ever operate properly? If you
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