[Gmecm] On the fly tuning

[Craig Moates]

Steve,

Yes, that's right. You can disable the onboard flash nicely that way. I've done that already, where you force the ROM CE high and
you can essentially throw the whole onboard Flash into high impedance mode. Then you can apply your own bootstrap RAM/etc to shadow
the ROM code and act as an emulator. That way you don't even have to remove the Flash chip to achieve the RT emulation, just disable
it by forcing the flash CE high.

I looked into doing something via dual port, but it ended up being a bit prohibitive in terms of architecture/availability/cost. I
ended up going with parallel battery-backed SRAM with decent logic in between for effective gating/muxing.

Here's a couple of pics of the present (and past) implementations:
www.moates.net/images/rr2/
That stuff all goes right off the pads of the flash location, not the edge connector, but it could be done on the edge connector as
well (install a little more tedious I suppose).

Best regards,
Craig Moates



----- Original Message -----
From: "Steve Ravet" <Steve.Ravet at arm.com>
To: <gmecm at diy-efi.org>
Sent: Thursday, June 29, 2006 4:50 PM
Subject: RE: RE: [Gmecm] On the fly tuning


As far as shadowing goes, one of the pins on the expansion connector is
a ROM disable signal.  You could add a dual port RAM to the connector,
copy the flash contents to the RAM, and get on the fly tuning via the
second port of the dual port.  I don't know about accessing CPU internal
memory, though.

--steve

> -----Original Message-----
> From: gmecm-bounces at diy-efi.org
> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Craig Moates
> Sent: Thursday, June 29, 2006 4:29 PM
> To: gmecm at diy-efi.org
> Subject: Re: RE: [Gmecm] On the fly tuning
>
> Darren,
>
> Sounds like some very nice and interesting stuff. I'd love to
> open a dialogue and help where I can. I've spent some time
> probing many of the edge connections to determine what is
> connected where and how they behave on the scope. One of my
> present interests is to develop an easy-to-use internal
> interface which would use some of the existing edge connector
> terminals to access RAM data within the CPU of the PCM. This
> could, in practice, allow high-speed data acquisition
> separate and apart from the DLC/OBD2 protocols. I'd started
> chasing the possibility of having external RAM to shadow the
> content in some way if the address or data lines were common
> with the Flash bus. However, a serial solution, even if a CPU
> code patch had to be applied via BDM, would be ideal I think.
>
> Best regards,
> Craig Moates
>
>
> ----- Original Message -----
> From: "Darren Freed" <darrenfreed at shaw.ca>
> To: <gmecm at diy-efi.org>
> Sent: Wednesday, June 28, 2006 10:03 AM
> Subject: Re: RE: [Gmecm] On the fly tuning
>
>
> > Yup - connected it to the edge connector.  I used CS8 for the CE
> > signal and CS9 for the OE signal.  Both of these chip selects
> aren't used in the stock code.  The SRAM is addressed to
> $B0000 and the address lines are connected as in the efi332
> project (ie leaving A1 not connected).  It worked well - no
> troubles at all.  I just need to work on the PC software now,
> to make it more user friendly.  Unfortunately I'm over in the
> UK now for a year, away from my ECM bench.  So everything for
> the next year will be PC programming stuff.
> >
> > On another note, I've been looking at the DLC routines
> quite abit in a
> > variety of V6 and V8 code, from '96 to '04.  It seems
> pretty well conserved throughout, which is good news in terms
> of developing an interface and programming for datalogging/reflashing.
> Although my SCI stuff works well for me, its not particularly
> useful to anyone else (I suspect).
> >
> > Darren
> >
> >
> > ----- Original Message -----
> > From: Steve Ravet <Steve.Ravet at arm.com>
> > Date: Wednesday, June 28, 2006 0:06 am
> > Subject: RE: [Gmecm] On the fly tuning
> >
> > >
> > >
> > > > -----Original Message-----
> > > > From: gmecm-bounces at diy-efi.org
> > > > [gmecm-bounces at diy-efi.org] On Behalf Of Darren Freed
> > > > Sent: Sunday, June 11, 2006 1:12 PM
> > > > To: gmecm at diy-efi.org
> > > > Subject: [Gmecm] On the fly tuning
> > > >
> > > > So I'm one step closer to on the fly tuning with a GM
> OBDII pcm.
> > > > I've added an additional 16k sram and am able to write
> to it and
> > > > read from it with SCI(ALDL) type comms - ie modify
> tables on the
> > > > fly.  This is similar to what is done with the
> > > > efi332 project.
> > >
> > > Darren, where (physically) did you connect the SRAM?  To the edge
> > > connector?  Did you use an unused chip select output, or did you
> > > replacean existing item in the CPU memory space?
> > >
> > > --steve
> > >
> > >
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