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Few QuickStart board specific questions, — Parallax Forums

Few QuickStart board specific questions,

rwgast_logicdesignrwgast_logicdesign Posts: 1,464
edited 2012-08-26 10:31 in Propeller 1
So basically i started out running home made prop boards, but recently have blown up a few wal warts!! I bought a quick start a while back then won another one the other from propeller powered (thanks you jeff!!). I like them becuase I can fit them in an altoids tin along with a usb cable jumper wire a blue tooth serial dongle and a few other things. Makes a great little kit for when im away from home!

Anyways ive just recently started using these quick starts on my desk becuase, well I am just to cheap to go buy another universal wal wart, and i dont wanna hack the ends off any I have laying around. One of the projects im doing acually happens to only need 8 led's and 8 buttons too so this board is super perfect for that leaves me free to build more important things!

As long as im around a PC and dont need to OC the prop I love these little guys. BUT there is something driving me insane!!!!!!! The blue leds!! If I dont need them is there an easy way to disable them?!!! I need to use a few of the pins there attached too as outputs so obviously thats gonna flip them on, but for some reason they turn on when i just insert a piece of jumper wire into the header with the pin in hi-z, whats that all about??

I also just have a few questions about the board itself. There is a patch of through holes labeled with greek letters, im assuming that they are sigma/delta, the triangle and the e thing. What exactly would you solder there, and what are all the surface mount pads above those holes for? They obviously all dont turn brown out on and off? Last thing is inbetween the LEDs and chip there are two resistor networks, but between the resistors and prop there is a 74hc541, I thought these were primarly used to translate 5/3.3vs what the function of the hc541 on the quickstart board?

Comments

  • Tracy AllenTracy Allen Posts: 6,664
    edited 2012-08-26 10:30
    You can download the quickstart schematic and the layout diagram from the Parallax quickstart page. The 74HC541 has high-Z inputs that sense the state of p16 to p23, so that the LEDs can be lit without affecting loading the pins. When you hang a wire or touch those inputs, there is an antenna effect that can pick up AC voltage that drive the 74HC541 through its switching threshold and turn on the LED. The associated Prop pin also has to be an input. Cover the LEDs with duct tape!

    Screen shot 2012-08-26 at 10.17.32 AM.png

    The extra pads are indeed for the optional sigma-delta circuit as seen in the diagrams.
    There is also an option to move R12 so that the BOE pin connects to Vdd=<brownout-disabled> instead of the default, which is Vss=<brownout-enabled>.
    quicstart_sigdel_layout.png
  • LeonLeon Posts: 7,620
    edited 2012-08-26 10:31
    See the schematic for the ADC components and use the values in the Obex, according to your requirements.
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