[Gmecm] Any USB developers out there?

[Bill Shaw]

Hi Steve,

I've written a tutorial on surface mount assembly,  you can see it here....
http://articulationllc.home.comcast.net/sm0402.htm

Realistically,  0402 assembly is tough,  you're much better off sticking 
to 0805 if you can. 

hth,

Bill


Steve Ravet wrote:
> Hey Craig, thanks for sharing.  I have a few questions:
>
> Is the 9 pin to OBD2 cable something that is standard or one of your
> cables?  I used a DB-15 on mine, but was planning on moving to a DB-25
> to allow more of the PIC pins to be pinned out (ie misc analog and
> digital I/O).  But if the DB9 is standard I may switch to it.
>
> I guess you use solder paste to do 0402?  In your experience (or anyone
> else), does solder paste really go bad within a month?
>
> After looking at yours I realized there's no reason to have the 5V
> regulator in there, might as well always have the VCC stuff powered from
> USB.  Eliminates parts and makes the BOM that much cheaper.  I'm also
> going to use your board layout to fit the Pactec enclosure.
>
> I'm writing my firmware in C, since microchip assembly makes my head
> hurt.  As far as the host interface, I had planned on implementing the
> SAE J2534-1 API.  (Yes, this is an SAE spec that specifies a windows
> API).  This is a standard API for vehicle reprogramming but the API is
> generic enough to work for normal scan tool operations also.  The spec
> requires support for all vehicle protocols but USBVPW will only do VPW.
> That SAE spec is now on the USBVPW wiki page, take a look.
>
> What do you think your BOM cost is, including the PCB?
>
> Speaking of PCBs, I have a number of small (couple square inches or
> less) projects I've been wanting to do but it seems like most PCB houses
> get offended if you do arrayed PCBs.  Is there a PCB place that will do
> a 4x6 PCB with many individual circuits on it and not want to give me
> all kinds of per project charges?  Otherwise the cost for these one-offs
> is prohibitive.
>
> --steve
>
>   
>> -----Original Message-----
>> From: gmecm-bounces at diy-efi.org 
>> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Craig Moates
>> Sent: Monday, December 25, 2006 3:01 PM
>> To: gmecm at diy-efi.org
>> Subject: Re: [Gmecm] Any USB developers out there?
>>
>> Folks,
>>
>> I updated the layout, and it's probably ready for a proto 
>> run. Check it out if you like:
>> www.moates.net/projects/
>> Got tired of trying to squeeze those beefy 1206s in there so 
>> went to mostly 0402. They're doable with magnifier and tweezers.
>>
>> All the components are specified, laid out pretty well, and 
>> labeled on the schematic and silkscreen.
>>
>> I'll start working on the firmware shortly. Prefer C++ or 
>> ASM? Guess I'll make it compatible with some of the 'other' 
>> stuff out there.
>>
>> Best regards,
>> Craig Moates
>>
>>
>>     
> _