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Propeller 2 Breadboard Breakout — Parallax Forums

Propeller 2 Breadboard Breakout

TubularTubular Posts: 4,702
edited 2013-02-20 18:06 in Propeller 2
This is my take on a breadboard breakout ("breadout?") for the prop 2.

It includes flash, temp compensated xtal oscillator, LDO regulators. It may even include a FT232R before the weekend is out, and if it fits.

It can be used stand alone, or castellated along the "C" for cut lines, and soldered to the back of a full size breadboard, to provide clean breadboard playground where any node can have signal injected (sine, current source, dac, etc) or measured (adc). This will lead to lots of fun.

Along one side I have added intermediate nodes for construction of external R2R dacs, audio filters, led resistors etc. Along the other side servos or sensors can be connected with the usual 3 pin headers.

I think it would be fun to hook up a projector aimed at the front of the breadboard and have the Prop2 itself project Fritzing style circuits, overlaid with live node status (voltages,timing info, waveforms etc) in real time, adjacent to the nodes. I'm also looking at an aligned LCD to do the same without projection hassle.

Thanks to jmg for the parts suggestions.
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Comments

  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2013-02-15 10:34
    This looks awesome, well done.

    Only one purely selfish nit to pick; could you swap the pwr/gnd rails on the lower edge so that GND is next to the pin connections? The reason I ask for this is because then I can connect the .100" IDC connector on my logic analyzer directly to the board and don't have to use pods and flying leads.

    --EDIT--

    Thinking about this some more, a few minutes with an xacto knife and two jumpers and I can do this myself. So, never mind. ;)
  • jac_goudsmitjac_goudsmit Posts: 418
    edited 2013-02-15 11:05
    Just a thought: I wonder how hard it would be to create a PCB for the P2 that would be similar to Tubular's but would have all pins exposed on one edge of the PCB, leading to two single-row 90 degree 50 pin IDC headers: one on the top side and one on the bottom side. If it's possible to do this and create a 0.3" space between the pins of the connector and make the pins come out equally far (even though they obviously have to be staggered somehow) it would be possible to plug it into a normal breadboard. The PCB would be standing upright in the middle of a breadboard (the whole contraption would look like in inverted letter T).

    Obviously the servo-type connections on Tubular's board would be very useful too, but I reckon the possibility of using a (large) breadboard or a multi-breadboard setup would be interesting to at least some users...

    ===Jac
  • BigFootBigFoot Posts: 259
    edited 2013-02-15 12:52
    Tubular wrote: »
    This is my take on a breadboard breakout ("breadout?") for the prop 2.

    It includes flash, temp compensated xtal oscillator, LDO regulators. It may even include a FT232R before the weekend is out, and if it fits.

    Nice work, I like the way you turned the chip 45° to get all the signals and power out.
  • jmgjmg Posts: 15,173
    edited 2013-02-15 13:32
    Tubular wrote: »
    It includes flash, temp compensated xtal oscillator, LDO regulators. It may even include a FT232R before the weekend is out, and if it fits.

    Certainly a good idea, you could try the FT230X / FT231X ?
    These newer variants have better split power tolerance, and are smaller packages.
    Not sure where they are in a errata cycle, but I see Parallax already use them.

    Are there any SMD decoupling on the rear, under the package ? Hard to see on the image.
    Also a little hard to see on the image, is the GND connections, from the chip-core to the IO ring ?
    I think there is room to run GND lines between the 0.1" IO stripes ?
  • TubularTubular Posts: 4,702
    edited 2013-02-15 15:23
    jac_goudsmit wrote: »
    Just a thought: I wonder how hard it would be to create a PCB for the P2 that would be similar to Tubular's but would have all pins exposed on one edge of the PCB, leading to two single-row 90 degree 50 pin IDC headers: one on the top side and one on the bottom side. If it's possible to do this and create a 0.3" space between the pins of the connector and make the pins come out equally far (even though they obviously have to be staggered somehow) it would be possible to plug it into a normal breadboard. The PCB would be standing upright in the middle of a breadboard (the whole contraption would look like in inverted letter T).

    Obviously the servo-type connections on Tubular's board would be very useful too, but I reckon the possibility of using a (large) breadboard or a multi-breadboard setup would be interesting to at least some users...
    ===Jac

    Jac actually the predecessor to this, based on three cascaded prop1s, was pretty much as you described. The trick to adapting it is a Samtec passthrough box header, type BCS (or similar). I couldn't find it in these forums, perhaps I forgot to post it. Here are some photos now. The trouble is is all ends up being over an inch high, and you end up with a kind of 'wall' through the middle of your proto area, which is why I like the idea of soldering underneath.

    @martin, the same box header arrangement might save you even the trouble of having to break out the exacto knife
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  • TubularTubular Posts: 4,702
    edited 2013-02-15 16:43
    jmg wrote: »
    Certainly a good idea, you could try the FT230X / FT231X ?
    These newer variants have better split power tolerance, and are smaller packages.
    Not sure where they are in a errata cycle, but I see Parallax already use them.

    Yes there is no doubt they would fit nicely. I think they sorted out the data stream reset issue but haven't followed it that closely.
    jmg wrote: »
    Are there any SMD decoupling on the rear, under the package ? Hard to see on the image.
    Also a little hard to see on the image, is the GND connections, from the chip-core to the IO ring ?
    I think there is room to run GND lines between the 0.1" IO stripes ?

    No decoupling on the reverse, but I'll add some in since there are those long voltage rails there anyway. I was trying to keep it flat on the reverse, but its a good idea to have spare pads there in case the front decoupling caps aren't sufficient.

    And the ground lines between the stripes is also a good idea, and easy enough to do. I'll just check clearances but I think you get a pretty good isolation effect even with a narrow ground line

    Thanks for your feedback jmg, I appreciate it.
  • jmgjmg Posts: 15,173
    edited 2013-02-20 03:18
    .. another part you may have room for, is the LXDC2HL18A-052 from Murata.
    This is a little DC-DC block, 1.8V @ 600mA min, inductor included, ~ $1.93/100+, and just 2.5x2.0mm
    This series is not adjustable, but is small enough to paste in somewhere as an option ?
  • TubularTubular Posts: 4,702
    edited 2013-02-20 04:15
    Another nice find jmg. What an incredible package construction, and only 1.1mm high.

    I think its probably a bit borderline for this application - that 600ma starts to derate sharply above 40 degrees C ambient, and ideally you'd allow a bit more current too, but I'm really impressed with the package. I can think of plenty of other things to do with it
  • Cluso99Cluso99 Posts: 18,069
    edited 2013-02-20 18:06
    Here is a 5V switching reg that might go with those LXDC2HL chips... R-78E5.0-0.5 It is a large TO220 style package, 28Vin but only 500mA.
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