[Gmecm] Any USB developers out there?

[Jay Shroff]

There seems to be a competitor to ELM who posted on this list
 
www.obdpros.com
 
Maybe they are willing to provide the micro's at a much lower cost than ELM. I have been playing around with one of those devices and it seems to be able to keep up with a pretty busy J1850 bus on a 1996 Chevy Avalanche.
Jay



> Date: Thu, 21 Dec 2006 10:30:38 -0500> From: b.shaw at comcast.net> To: gmecm at diy-efi.org> Subject: Re: [Gmecm] Any USB developers out there?> > Motorola has discontinued almost everything containing a BDLC, says > J1850 is loosing popularity. The only thing they still have in the > product line is a couple of HC12 variants with BDLC. GM is going all > CAN as of 2008. Bit-banging looks like the only real alternative > besides ELM for new devices, and ELM is just a bit banging > implementation itself.> > Bill> > Craig Moates wrote:> > Bill,> >> > This is in Cadsoft Eagle 4.16 (www.cadsoft.de), it should fit in the > > 'Free' version but I haven't tried it that way.> >> > Agreed on the 68HC58, it is obsolete. But I've got a few hundred > > laying around from another project so figured I'd try and make use of > > it. Plus you can still get it from sources like www.newark.com I think > > they have 700+ in stock at sub $4 each. Eventually it'll dry up in > > terms of supply, and the design will need to be updated.> >> > Are there any updated chipsets which would handle all the VPW timing > > and encoding including 4x? I've seen the line level stuff like the > > MC33990, but you have to do all the pulewidth management at the micro > > side. I think that would be a great way to go, but would put more > > burden on the firmware development side. Maybe eventually, but for a > > quick-hit, the 68HC58 should cut it. Open to other ideas though.> >> > Best regards,> > Craig Moates> >> >> > ----- Original Message ----- From: "Bill Shaw" <b.shaw at comcast.net>> > To: <gmecm at diy-efi.org>> > Sent: Thursday, December 21, 2006 7:32 AM> > Subject: Re: [Gmecm] Any USB developers out there?> >> >> >> 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> > _______________________________________________> Gmecm mailing list> Gmecm at diy-efi.org> Subscribe: http://lists.diy-efi.org/mailman/listinfo/gmecm> Main WWW page: http://www.diy-efi.org/gmecm
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