[Gmecm] Any USB developers out there?

[Bill Shaw]

Hi Craig,

What schematic capture are you using for this?  The first problem I see 
is the 68hc58,  Freescale says it's obsolete and not recommended for new 
designs.

Best,

Bill

Craig Moates wrote:
> Steve,
>
> I've put together an 'alternate' layout for USB-to-VPW. Feel free to 
> take a look. I have yet to stitch together all of the connections, but 
> given about an hour or so, it can be cleaned up and made to be pretty 
> tight. Check the readme.txt for comments.
>
> I just did it from scratch, based on the datasheets and takeoffs from 
> what I've done before. But it could be made to be pretty tight and 
> workable, and very low cost as well. It doesn't have integrated USB in 
> the micro, but on the other hand, it would be able to use standard COM 
> port protocols. You could set it up with a bootloader as well to make 
> it field updateable.
>
> Y'all are welcome to play however you like. I'm going to beat on it 
> some more and get all the connectivity together. Might even hit on the 
> firmware if I can find a spare day or two. Ha! Feel free to put it in 
> as part of the Wiki for the GMECM stuff. It's a work in progress to be 
> sure, but I figured I'd share what I had thus far.
>
> www.moates.net/projects/class2/
>
> Best regards,
> Craig Moates
>
>
> ----- Original Message ----- From: "Steve Ravet" <Steve.Ravet at arm.com>
> To: <gmecm at diy-efi.org>
> Sent: Sunday, November 19, 2006 11:41 PM
> Subject: RE: [Gmecm] Any USB developers out there?
>
>
>
>
>> -----Original Message-----
>> From: gmecm-bounces at diy-efi.org
>> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Craig Moates
>> Sent: Thursday, November 09, 2006 11:51 AM
>> To: gmecm at diy-efi.org
>> Subject: Re: [Gmecm] Any USB developers out there?
>>
>> Steve,
>>
>> Definitely check the crystal and capacitor areas. Those are
>> ceramics you are using for the 18pF set? Check that it's set
>> up for 18pf on the xtal desired capacitance?
>
> The crystal is 20 MHz 18pf according to the digikey datasheet.  They're
> ceramic caps.
>
> I don't know what the problem with the crystal circuit is, but I removed
> it and used a 4 MHz OSC instead, changing the firmware accordingly, and
> now it works.  I tried with and without the load resistor (on the
> crystal) but no change.  The demo board has an external load resistor
> but the data sheet shows a resistor internal to the part.
>
> I decided that I want USB power after all so I can reflash the PIC
> without external power.  You mentioned the circuit you use but I can't
> find the note now.  What is it?
>
> Craig, what do you use for schematic capture and PCB layout?
>
> Maybe there'll be a USB <-> VPW project working by Christmas now...
>
> thanks for the suggestions everyone,
>
> --steve
>
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