[Gmecm] Any USB developers out there?

[Programmer]

Hey Craig,

I see the new board is quite a bit smaller...nice work !

Lyndon.

----- Original Message ----- 
From: "Craig Moates" <craig.moates at cox.net>
To: <gmecm at diy-efi.org>
Sent: Wednesday, November 22, 2006 8:37 AM
Subject: Re: [Gmecm] Any USB developers out there?


> Steve,
>
> Ok, cool. That all sounds consistent then. Glad it's going! Maybe the xtal 
> frequency needs to be accounted for appropriately in the PIC's fuse bit 
> settings? Like a clock divisor for the USB bus? That'd be sweet if that's 
> all it is.
>
> I've been using Eagle 4.16 for pretty much everything. Some folks groan 
> about it, but in my experience, everything has a downside. But it gets the 
> job done and helps greatly when it comes to exchanging ideas and 
> information.
>
> If you'd like me to take a stab at revising the layout, I'd be happy to. 
> I've done some work around trying to optimize the 68HC58 incorporation. 
> Here's one that I did:
> http://www.moates.net/images/rr2/rr2_compare.jpg
> Top right of leftmost picture. Been going to smaller 0402 components, 
> they're sweet ;^).
>
> 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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