Parallax FLiP Schematic ?

jmgjmg Posts: 11,062
edited May 2017 in Propeller 1 Vote Up0Vote Down
I see the Propeller FLiP microcontroller module is taking pre orders.
Is there a link to the schematic anywhere ?
I want to check did Parallax remember to support (optional) hardware handshake lines, to the FT231X, to allow higher speeds ?


  • 6 Comments sorted by Date Added Votes
  • I'm sure we'll get one posted pretty soon. Ken Gracey
  • jmgjmg Posts: 11,062
    edited May 2017 Vote Up0Vote Down
    The SCH files are now up, somewhat hidden inside

    Seems there are no hardware handshake lines connected, not even optionally. :(
    Perhaps they can be added on the next board revision ?

    I see the oscillator is SIT8918BE-13-33E-5.000000G
    The first “3” is for ±50 PPM, ( SiTime make down to ±20 PPM ) but the data suggests typically they are better than that ±50 PPM

    A useful example project would be to run
    connected to the Parallax GPS module 1pps, and store the result into high-eeprom, so as to ship an Osc calibration value with each PCB ?

  • jmgjmg Posts: 11,062
    SIT8918BE ppm plots, for 20 samples from data
    480 x 380 - 32K
  • Just curious: Is FLiP an acronym?
    Ken Gracey wrote: »
    I'm sure we'll get one posted pretty soon. Ken Gracey

  • There are a couple of parts there from companies I was not aware of before, Alpha & Omega Semiconductor for the AOZ1281DI buck regulator and Richtek for the RT9728BLGQW programmable current limiter, and SISTIME for the 5MHz mems oscillator. It is always an engineering challenge to take on designs with new parts. Parallax has really bent over backwards to protect these boards from release of the magic smoke. The connections to the power source signals on the FT231X is clever, to program current limiting based on the type of supply available.

    One beef I have is with Q201, the reset transistor. That should really be a digital transistor, rather than a generic MBT3904. A digital transistor fits in the same footprint and then doesn't need R201, but it adds a resistor in series with the base. As shown, capacitor C202 is tied directly to the base, and the reset signal can be very ugly with oscillations. Probably doesn't matter in most cases, but we've had suspicions, and I'd just prefer a clean reset pulse.
  • DaveJenson wrote: »
    Just curious: Is FLiP an acronym?

    For Learn 'ing Propeller?
    Fun Lov 'in Propeller?

Sign In or Register to comment.