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PropPlug vs QuickStart schematic for DIY FTDI breakout — Parallax Forums

PropPlug vs QuickStart schematic for DIY FTDI breakout

angrywaspangrywasp Posts: 2
edited 2012-12-30 16:32 in General Discussion
Hi all,

I bought my propeller about 6 months ago and finally have a chance to get to know it :smile: Anyway, i have made a simple breakout board for the prop, which is working well, but i would now like to work on a schematic for my own ft232rl based serial board. i had one quick question before i got to it though. i have examined the PropPlug and QuickStart schematics around the FTDI chip, and i have noticed them to be quite different (Besides the different pins for the different packages). The use of the 74LVC126A and different value components around the reset circuit on the QuickStart are catching my attention. i was wondering if there are any pros/cons to each of these designs, and which one i would be best following to making my own compatible circuit.

Thanks

Comments

  • SRLMSRLM Posts: 5,045
    edited 2012-12-30 01:08
    Welcome to the forums.

    The FTDI circuit on the quickstart (and all recent Parallax designs) is to overcome the FTDI reset issue: http://forums.parallax.com/showthread.php?116711-Can-Parallax-do-something-about-the-FTDI-reset-bug

    I would recommend going with an appropriate circuit. Personally, I use the circuit from post #7 from the link above. I do not follow the Quickstart FTDI circuit directly since it has a quad buffer, and it buffers the two extra lines (that I don't need or use). You can also look at the Eddie control board schematic for a recent design. http://www.parallax.com/portals/0/downloads/docs/prod/robo/eddie/220-28990-EddieControlBoardRevA.pdf
  • angrywaspangrywasp Posts: 2
    edited 2012-12-30 16:32
    Thanks for the reply. gives me a few things to think about. I have a few 74LVC126A parts on hand which i may use, because the breakout board i want to make will have more uses beyond the prop, and there are none of the 2G07 parts on ebay at the moment.

    I had to ask about these schematics because i had an existing FTDI breakout to get serial data from a GPS module to my PC (which works btw), but when i added the reset circuit, the spin tool didn't detect the prop. So probably better to build another from scratch.

    So thanks again, and when i get enough time off work to make another board i'll let anyone interested know how it went
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