Shop OBEX P1 Docs P2 Docs Learn Events
Using quickstart board as stand-in for propplug in a pinch? — Parallax Forums

Using quickstart board as stand-in for propplug in a pinch?

KeithEKeithE Posts: 957
edited 2014-08-30 14:20 in Propeller 1
If one were to hold the propeller chip in reset, then could one use a quickstart board as a stand-in for a propplug to program another board? Just asking since this might come in handy for a project with my nephew over the long weekend. I don't have a chance to purchase another propplug or equivalent for him, but have some $7 quickstarts from the radio shack clearance. But I don't want to rework them for this.

The datasheet says "P30 - Serial Tx to host" ... "upon power-up/reset" but I'm not sure if this is while reset is asserted, or after it is released.

Is there anything else that I might have missed?

Edited to add: I assume I may have to do something with DTR, but I'm mostly wondering about P30.

Comments

  • kuronekokuroneko Posts: 3,623
    edited 2014-08-29 17:27
    In case you have direct access (res/rx/tx) to the other prop check out this object http://obex.parallax.com/object/472.
  • KeithEKeithE Posts: 957
    edited 2014-08-29 18:14
    That's interesting and I'll take a look. Would that allow propterm to work as well? And at arbitrary baud rates without having to reprogram the quickstart? I should have mentioned this in the wishlist.

    Edited to add: I guess it should be easy to edit this to allow serial pass-through at a fixed baud rate after programming is done. Would work in a pinch. I'll put a pullup and then pulldown on P30 and see if it's floating during reset and see what it's doing.
  • kuronekokuroneko Posts: 3,623
    edited 2014-08-29 18:26
    KeithE wrote: »
    That's interesting and I'll take a look. Would that allow propterm to work as well? And at arbitrary baud rates without having to reprogram the quickstart? I should have mentioned this in the wishlist.
    What's the (post download) job of the QS?

    One way of doing it would be to download a boot image to the QS, it then programs the second prop and subsequently links the 2nd prop's rx/tx lines to its own rx/tx (assuming you want the 2nd prop to talk to PropTerm). Then it either idles or does something else. I have setups like this up and running (demoboard/QS+HIB and a RAMBlade).
  • KeithEKeithE Posts: 957
    edited 2014-08-29 18:53
    >What's the (post download) job of the QS?

    Emulate a propplug which would allow the host to talk to the prop that was just programmed. Since the FTDI logic solves the hard part, the QS propeller would just have to pass-through serial traffic. Eventually this would be replaced with a propplug or perhaps http://www.pololu.com/product/1308 - it's just that I didn't think about this shortage in time for the weekend. I thought that just wiring up to the FTDI and holding the prop in reset with a jumper to ground would be the easiest. If P30 is high-Z during reset, then I only have to worry about wiring to DTR and will probably go that route since it's the closest to a propplug.

    Why not just do everything on the QS - I want to hookup to a prop on a breadboard which will allow him to hack around a bit. Think a DIY version of the educational kit. (I have extra parts but don't want to give up my QS permanently. So it will just be doing this for the short term.)
  • abecedarianabecedarian Posts: 312
    edited 2014-08-29 19:58
    Fry's has an OSEPP FTDI USB-TTL serial breakout board, supposedly in stock at the San Jose location.
    http://www.frys.com/product/6997547
  • KeithEKeithE Posts: 957
    edited 2014-08-29 21:45
    abecedarian - thanks for that information. It didn't occur to me that Fry's would even carry this. You're right - all of the Fry's in the South Bay have this in stock.

    On a separate note have you ever seen one of these stock that goes down to 1.8V? One of my coworkers is tired of modifying them. He typically buys from either Polulo or Sparkfun and always has to rework them. Traditionally he was pushing the Silicon Labs CP21xx devices, but I believe he's looking more at FTDI due to higher baud rates. e.g. 3 MBaud which we need for testing our ASICs. I don't need any of these features for home use yet, but if anyone has recommendations I'll pass them on.
  • abecedarianabecedarian Posts: 312
    edited 2014-08-29 23:20
    Don't know of any modules.
    FTDI has some cables with the chip in one end and bare wire at the other that can go down to 1.8.
    Fourth one down in the table here: http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm
    It supplies 1.8v logic and VCC.
  • KeithEKeithE Posts: 957
    edited 2014-08-30 10:24
    I did the Fry's/Noah's run this morning and picked up a couple. I'll see if my coworker is interested in the cable. He's often cobbling together internal dev systems, and might not want a cable permanently attached. It's not too difficult to rework the boards, but it takes additional. I don't know if he's given feedback to the various suppliers - 1.8V I/O is pretty mainstream these days (e.g. in smartphones, tablets,...), but maybe they sell the majority of these adaptors to hobbyists using older standards.
  • abecedarianabecedarian Posts: 312
    edited 2014-08-30 11:37
    There is the option of throwing a header on the board and then a matching connector on the cable.
  • KeithEKeithE Posts: 957
    edited 2014-08-30 12:50
    To be honest I don't know why he hasn't designed his PCB by now, and offered the design to others for free. He is a PCB designer/apps engineer at a large company, so he has plenty of resources available. And he basically has the schematics done, they are just embedded inside of larger PCB designs. (He often has to adapt to even other designs which don't contain said logic.) Oh well - I was thinking of recycling one of his old eWaste eval kits as a prop plug, but the QS seemed simpler, and then Fry's was even better ;-)
  • PublisonPublison Posts: 12,366
    edited 2014-08-30 12:58
    KeithE wrote: »
    To be honest I don't know why he hasn't designed his PCB by now, and offered the design to others for free. He is a PCB designer/apps engineer at a large company, so he has plenty of resources available. And he basically has the schematics done, they are just embedded inside of larger PCB designs. (He often has to adapt to even other designs which don't contain said logic.) Oh well - I was thinking of recycling one of his old eWaste eval kits as a prop plug, but the QS seemed simpler, and then Fry's was even better ;-)

    I must have missed this, but who is "he" ? I don't see any links.
  • KeithEKeithE Posts: 957
    edited 2014-08-30 14:20
    The same guy referenced in "One of my coworkers is tired of modifying them" earlier. All of his PCBs are unfortunately not public, but the FTDI or CP21xx part of them is nothing special. He should consider making those separate modules, and see if he could open that part up. Because right now he has to purchase and modify 3rd party modules for other boards. Or if anyone else makes a module that can operate at 1.8V in both FTDI/CP21xx flavors he will buy them. But this is not for volume designs, so not too exciting. Others would probably buy them as well since it's a bit of a hole as far as I can tell. Anyways - back to seeing if I was given the wrong parts at Anchor for my weekend project, and maybe off to Fry's again…

    Edited to add: Anchor got it right. Took me a while to get my Saelig microscope working again.
Sign In or Register to comment.