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What are the two capacitors for between the BS2 and the PC Serial port? — Parallax Forums

What are the two capacitors for between the BS2 and the PC Serial port?

hottnikks36hottnikks36 Posts: 8
edited 2006-01-12 22:09 in BASIC Stamp
Hello,

in the schematic on how to connect the BS2p to the serial port of a computer, it shows that there are two 0.1uf caps before pin3 and pin4 of the BS2. I was just wondering what's the use of these caps, and what would happen if i wanted to connect a serial cable directly to the BS2, without the caps. (i haven't tried it yet, but it's very tempting since i dont have any caps laying around :P)

Thanks again

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-01-12 05:16
    This was just covered a few threads down.· See my post in the following thread.

    http://forums.parallax.com/showthread.php?p=566239

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • allanlane5allanlane5 Posts: 3,815
    edited 2006-01-12 14:08
    In short -- they decouple the 'reset' DTR signal, so if some application (like Hyperterm) holds it 'active', the BS2 can still run. Without them, Hyperterm holds the BS2 in reset.

    So, as long as you disconnect the DTR line, or don't want to reset your BS2, or control the DTR line in your own code, you can leave the capacitors off.
  • hottnikks36hottnikks36 Posts: 8
    edited 2006-01-12 22:09
    Thanks, didnt notice the other thread.

    Thom
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