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Replacing the Prop Plug with Sparkfun's Breakout Board for FT232RL USB to Serial — Parallax Forums

Replacing the Prop Plug with Sparkfun's Breakout Board for FT232RL USB to Serial

blittledblittled Posts: 681
edited 2011-02-09 20:53 in Propeller 1
I'm breadboarding a circuit and would like to power it via USB so I got Sparkfun's Breakout Board for FT232RL USB to Serial http://www.sparkfun.com/products/718. That should provide 5V and 3.3V at up to 500mA. My question is should I use a 2N3904 NPN transistor on the DTR line before tying it to the RES input of the Propeller?

Comments

  • BTXBTX Posts: 674
    edited 2011-02-09 12:22
    Copy the demo boards schema, and if you'll program the pchip with this, yes, you should add that.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-02-09 17:43
    Yes, you need the transistor circuit. Any npn should do. I use the P2N2222A. Use a series resistor in both the TXD and RXD leads just in case. The circuit recommends 150R and you can use higher, say 1K. If you connect the VccIO to the 3V3out pin to power the I/O at 3V3 you could dispense with the series resistors but they are a safety precaution. I tried to locate the circuit I based my TriBlade on but it apears to have been updated, so look at sheet 4 of my Triblade schematics - try the TriBladeProp thread or my web www.cluso.bluemagic.biz
  • blittledblittled Posts: 681
    edited 2011-02-09 18:44
    Thanks for all the input! I do have the Hydra schematics which uses the 2N3904 but was having trouble with communicating with the Propeller. That turned out to be a cold solder joint in a 3.3V regulator board I used temporarily for setting up a basic Propeller circuit as per the schematic on the download page. I got it working and the USB line is powering the circuit.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-02-09 20:53
    Excellent. Glad it's up and running :)
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