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Any interest in an all through-hole USB Propeller dev board? — Parallax Forums

Any interest in an all through-hole USB Propeller dev board?

RevAaronRevAaron Posts: 30
edited 2009-09-18 18:43 in Propeller 1
One of the complaints a lot of folks when getting USB going on a DIY Propeller board or Arduino is that the FTDI chip isn't terribly hobbyist friendly, being an SMD device. Towards the end of getting something easier to assemble for folks without the ability to handle SMD I am working on a USB Prop board that is all through-hole, with a PIC18LF2553 replacing the FTDI232 and providing the same USB to UART functionality. I've got a setup working with the PIC18F4550, and will be working on a board using the smaller PIC18F2553 over the next few weeks.

Anywho... This is one of those things that probably doessn't have too much appeal- but for folks who would rather not depend on SMD for DIY it could be quite handy. I'm just wondering if anyone would be interested in PCBs, pre-programmed USB-to-UART PDIP chips, or even PropPlug work-a-like through-hole kits. I'll be working on some of this regardless, but if other people are interested I can look into Gadget Gangster or getting some PCBs made for a USB Prop board using this kind of setup.

thanks!

Regards,
Aaron

Comments

  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2009-09-18 04:50
    I think you could definitely receive some level of interest for DIY setups. If it's in a DIP package, I wouldn't bother with any PCB offerings especially if the entire circuit can fit on a proto board like the 2"x3" style

    What drivers would be needed for the computer?
    What other parts would be needed to complete the circuit? (can you post the schematic?)

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    WBA Consulting
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  • RevAaronRevAaron Posts: 30
    edited 2009-09-18 05:34
    I can totally work on a schematic. Right now, the setup is nothing but a breadboarded barebones Prop and a similar setup for the PIC on a prototyping PCB, with jumpers for RX, TX, and power from the PIC to the Prop.

    Driver-wise, I'm not sure. There is a way to make it a complete drop in for the FTDI, to the point where it would present itself as one, though that's probably more work than it's worth.

    On Windows and Linux, I think the driver is already built-in- Serial over USB is one of the core built-in classes for USB, like HID keyboards and mice. On the Mac I think a well, though I haven't tried it yet. You would need the MCHPUSB driver if you wanted to update the firmware on the PIC. A number of cool things would be possible though- it'd be easy to write a firmware that would allow us to select between the following modes:

    1. USB to serial for programming the Prop
    2. PIC Bootloader mode for updating the USB PIC's firmware
    3. HID Keyboard mode - shows up as a keyboard when plugged in, would allow the Propeller to appear as a keyboard, sending text to type via the UART
    4. HID Mouse mode - shows up as a standard mouse, allow the Prop to control the mouse
    5. Mass storage, and other possibilities: Something that the USB PICs support, though I don't know how it'd be used (yet!)

    All without having to dedicate additional IO pins or multiple Cogs to doing the USB work itself- which I understand, is possible for some uses, though not for actually loading the Prop.

    Anyone who has used the FTDI chip enough knows that it doesn't have sort of power- it is a USB to Serial chip first, last and always. I did try a demo today where I had the Propeller moving the mouse pointer back and forth using the USB PIC in HID mouse mode- no driver needed for that, to be sure!

    Aaron
  • Forest GodfreyForest Godfrey Posts: 38
    edited 2009-09-18 07:42
    I've used these PIC's a bit. The USB Bit Whacker (http://www.schmalzhaus.com/UBW/) uses them as well. There's a new one, too, the 18f13k50 (and several others in its series) that are available as 20 pin DIP.

    An idea I'm currently working on is using the mass storage device to allow a PC to copy files onto an SD card, which the Propeller can then mount, without removing the SD card from the circuit. I have a test board that should allow this - currently working on the software, though.

    Drivers (assuming the demo Microchjp software stack is loaded to the PIC): On Windows, the driver is built in, but you need a Microchip .ini file before the device will appear. Why? I have no clue - I don't claim to understand Windows. On the Mac, it "just works" and appears as a TTY in /dev. On Linux, it shows up, for inexplicable reasons, as an ISDN modem (at least on OpenSuSE 10), but that's just a serial TTY and you can echo commands to it just fine.

    Programming: A cool idea which I saw floated on this forum earlier is turning a Prop into a PIC programmer. Not sure if anyone actually did the software, though. That could, theoretically, give this setup a way for the Prop to reflash the PIC and vice versa!
  • fullspecengfullspeceng Posts: 76
    edited 2009-09-18 18:43
    I think DIYs must evolve and move to SMD.

    Ever since I released the direct inkjet PCB kits, making DIY PCBs is way easier and faster and moved completely away from through hole. Breadboards will always have their place but the time it takes to print out the pcb and etch it is much less than the time it takes for me to find out which jumper wire I misplaced.

    Drilling holes and through hole soldering is actually a lot more time consuming than a syringe, solder paste and a hot plate.

    After you get the hang of it, you can make a double sided PCB in 10-15mins start to finish using a fast etch like hydrogen peroxide and sulfuric acid.

    http://www.fullspectrumengineering.com/pcbinkjet.html
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