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I killed it. — Parallax Forums

I killed it.

Areal PersonAreal Person Posts: 197
edited 2006-11-30 03:46 in Propeller 1
I was wiring my version of a demo board, I was working with the TV video.
I by accedent ran one of the TV driver programs (may not have mattered anyway)
then, all the sudden I could not find the prop chip.

Is that possiable, All I had hooked up was the TV video through my homemade
3 resistor DAC. It is a portable TV running at 12vdc.

Could I have got feedback ? that blew up my chip or what ?

Thanks,
-Areal
·

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2006-11-29 23:25
    A video driver should not have been able to do anything harmful to your Propeller with a 3 resistor DAC connected. There must be something else with your setup. You'll have to post more information about your demo board version and the connections you made to it for us to try to help you further.
  • Areal PersonAreal Person Posts: 197
    edited 2006-11-30 00:09
    That was the setup, nothing else only the 3 resistors
    using the manuals setup diagram with propeller plug. (no eeprom)

    pins p12,p13 & p14 (1.1k, 560, 270)
    I grounded the jack on the board to the 3.3v ground

    I pluged the RCA cable in turned the TV on

    Found the prop with F7, and started running
    some on the TV demo programs.

    All the sudden, I got "No propeller found on COM1 etc.."

    And I have not been able to find it as of yet, I removed the chip
    from·the dip socket on my setup and put it on my breadboard according to the
    manual setup found in the manual.

    no luck. I'm not even close to being advanced with electronics,
    I'm a beginner, I however do program in C and I understand computers.

    Is it possiable for current to flow
    from the RCA plug into the Prop and overload
    kinda like blowing it out from the butt end ? (electrical implosion ?)

    The TV used 12vdc, but the powersource was well away from the
    solid 3.3 volt regulator I use for the prop (it's really a nice one)

    It was the software locking up the chip, or I got some kind
    of feed back.

    I had just tested the setup with flashing LED's just fine.

    What do you think Mike ?

    Could I have damaged my propeller plug also ?

    Thanks,

    -Areal

    ·
  • Mike GreenMike Green Posts: 23,101
    edited 2006-11-30 00:20
    Unless the TV is defective, it should not be possible to damage the Propeller by plugging the TV video input into it. The DAC resistors should protect the Propeller from damage in any event from low voltages (like 5V - which shouldn't be present on a video input [noparse][[/noparse]or output for that matter]).

    Check your wiring. Check your voltages with a meter.

    There's nothing that would feedback or lockup that would damage the chip and any software lockup would stop on the next reset.
  • Areal PersonAreal Person Posts: 197
    edited 2006-11-30 01:01
    OK Mike, If you say so, your the expert.

    I'll recheck everything, I'll try to be more
    carefull. I don't know what I could have done.
    But if you say it's not possiable, then ...

    Well, I must have done something I dont know about.

    Thank's for the help.

    I'm trying to build some of this stuff... Sometimes I'm over
    my own head [noparse]:([/noparse]

    Expert help like what you give, and what others give on the
    forum makes it possiable for folks like me to do some of this
    cool stuff. It's apprechated.

    -Areal
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-11-30 01:06
    Be sure your BOEn is connected correctly, and the RESn too. I had to reassemble my testbench today because I had a similiar problem, it was caused by the BOEn line (which I disabled through a pullup resistor) being disconnected.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Scott EScott E Posts: 7
    edited 2006-11-30 02:37
    Everyone has provided some great suggestions so after you have given them a try and you still cannot get the propeller to work then another possibilty may be ESD damage. Been a while since I researched ESD but as I remember it when you can feel a static discharge your body has reached a potential between 2-3kv (just a tad higher than 3.3vdc). At the high end of the scale the human body can charge to 30-35kv. That is not something a nice respectable propeller likes to have shot into it's body.

    Enough said on the topic be sure to follow proper ESD practices while making connections. All of us that have been doing electronics for a while can vouch for the results if you don't.
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2006-11-30 02:54
    If you have damaged some of your pins through ESD/overcurrent then there is a simple way to check for this. Just set your multimeter to diode check and probe each of the pins with the meter connected alternatively to VSS or VDD (with the chip out on a non-conductive surface). What you can deduce from this simple check is the integrity of parasitic diodes formed from the silicon substrate. direct.xilinx.com/bvdocs/appnotes/xapp329.pdf

    With the positive probe to VSS the port pins read around 420mv. With the ground probe to VDD the port pins read 630mv. The exact reading doesn't matter too much but you should find them in this general range however all the port pins should read much the same, any significant difference probably indicates a breakdown of the substrate.

    This method works well with ICs in general and is a standard test I perform when I suspect such a failure.

    *Peter*
  • Areal PersonAreal Person Posts: 197
    edited 2006-11-30 03:02
    Wow ! Now, thats some really cool advise !

    I'm going to check all my stuff, when I get back to work.

    -Thanks
  • Simon AmplemanSimon Ampleman Posts: 19
    edited 2006-11-30 03:06
    It's really hard to kill the chip "Areal Person"...

    I suggest you take a clean breadboard and start everything over... Double-check all cables.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-11-30 03:21
    I doubt it was ESD, we've had it tested and the only ESD vulnerable pins are the supply pins and those are the least likely pins you will touch first. The I/O pins exceed class III protection, the tester maxed out at 8kV and they didn't burn (the supply pins are class II).

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2006-11-30 03:29
    I doubt that it would be ESD myself but from experience I know that mixing power-supplies that may be plugged into different phases etc can result in some real shockers, not that this would seem the case either. But troubleshooting is a process of elimination, if the test is simple then do it and eliminate that avenue I say. Failure to eliminate simple avenues by chanting "It can't possibly be that" will probably invoke Muphy's first law [noparse];)[/noparse]

    Who hasn't burnt the midnight oil tracking down a fault only to find it was something really really simple, dumb, and of course it should've been obvious. Now talking about obvious has areal checked that the power supply is functioning correctly???

    *Peter*
  • Dennis FerronDennis Ferron Posts: 480
    edited 2006-11-30 03:46
    Check your serial cable, Prop plug, or USB serial adapter! If your connection from the computer to the Propeller goes bad, the PropTool won't be able to detect the Propeller whether it's good or bad. I had a similar problem with my suitcase computer - sometimes it wouldn't detect the Propeller, but I suspected the USB to serial adapter because I was having other problems with it. I narrowed it down to the USB plug by wiggling on different parts of the USB-to-serial cable to see what was loose. After I opened up the USB serial adapter and soldered in a USB cable I took out of an old mouse, I never had a problem programming the Propeller again.
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