[Diy_efi] Re: diy_efi Digest, Vol 17, Issue 11

Bill Washington bill.washington at nec.com.au
Sun Feb 13 23:58:39 GMT 2005


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Marcello,
    I would agree that switching in the middle of a read is likely to be 
the cause of the check engine light - When the switch over happens in 
the middle of a read you are probably going to get at least one 'bad 
read' - ie rubbish byte, and this could be anywhere in the program.......
    If you use the pic to do the switchover you should be able to 
control when it occurs - ie have it complete all processes/interrupts 
etc, suspend servicing any new ones, jump to a  switchover routine which 
can then achieve a clean switchover, then return to normal operation.

    I am a hardware engineer, not a software guru, so the description 
may be a bit simplistic, but I believe this approach should yield a 
viable solution.

Regards
Bill

>
>Message: 1
>Date: Thu, 10 Feb 2005 18:46:31 -0500 (EST)
>From: mbelloli at speedymotorsports.com
>Subject: [Diy_efi] Continuing the chip switcher problem
>To: diy_efi at diy-efi.org
>Message-ID:
>	<4860.67.121.93.112.1108079191.squirrel at www.speedymotorsports.com>
>Content-Type: text/plain;charset=iso-8859-1
>
>Hello Everyone,
>     I had asked the question eariler in regards to creating a mulitple
>bank chip switcher for an ecm.  Everyone basically said I should be
>able to just switch the chip without any regard for whether the chip
>is being accessed during the switch.  I finally got my pic chip
>controller up and running.  I'm running at 20mhz, and when I do a
>switch I'm still getting a check engine light.  2 out of three times.
> Thinking about this, I put the same exact bin in each of the banks
>of the chip, and still get the same response.  Could it not be that
>I'm switching in the middle of a read, and that is causing this
>problem???  What does everyone think.  If I turn the car off, and do
>the switch no problem.  I'm using this on a 1991 acura integra....had
>a 27c256 as the base chip, and I'm using a 29c010 as the replacement.
> I'm controlling the highest two address lines as bank select for a
>total of 4 banks.
>     I'll put the info for chip changer on my webesite, and add a link to
>it tonight.
>
>     Any ideas???
>
>Thanks,
>
>Marcello
>
>
>------------------------------
>
>Message: 2
>Date: Thu, 10 Feb 2005 18:57:41 -0500
>From: David Cooley <n5xmt at bellsouth.net>
>Subject: Re: [Diy_efi] Continuing the chip switcher problem
>To: A list for Do-It-Yourself EFI <diy_efi at diy-efi.org>
>Message-ID: <1108079861.4995.6.camel at n5xmt.bellsouth.net>
>Content-Type: text/plain
>
>I think it all depends on how the ECM is accessing the chip...
>I know this wasn't a problem on GM's at least thru 95...
>
>
>On Thu, 2005-02-10 at 18:46 -0500, mbelloli at speedymotorsports.com wrote:
>  
>
>>Hello Everyone,
>>     I had asked the question eariler in regards to creating a mulitple
>>bank chip switcher for an ecm.  Everyone basically said I should be
>>able to just switch the chip without any regard for whether the chip
>>is being accessed during the switch.  I finally got my pic chip
>>controller up and running.  I'm running at 20mhz, and when I do a
>>switch I'm still getting a check engine light.  2 out of three times.
>> Thinking about this, I put the same exact bin in each of the banks
>>of the chip, and still get the same response.  Could it not be that
>>I'm switching in the middle of a read, and that is causing this
>>problem???  What does everyone think.  If I turn the car off, and do
>>the switch no problem.  I'm using this on a 1991 acura integra....had
>>a 27c256 as the base chip, and I'm using a 29c010 as the replacement.
>> I'm controlling the highest two address lines as bank select for a
>>total of 4 banks.
>>     I'll put the info for chip changer on my webesite, and add a link to
>>it tonight.
>>
>>     Any ideas???
>>
>>Thanks,
>>
>>Marcello
>>
>>_______________________________________________
>>diy_efi mailing list
>>diy_efi at diy-efi.org
>>http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>    
>>
>
>
>------------------------------
>
>_______________________________________________
>diy_efi mailing list
>diy_efi at diy-efi.org
>http://lists.diy-efi.org/mailman/listinfo/diy_efi
>
>
>End of diy_efi Digest, Vol 17, Issue 11
>***************************************
>
>  
>

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Marcello,<br>
&nbsp;&nbsp;&nbsp; I would agree that switching in the middle of a read is likely to
be the cause of the check engine light - When the switch over happens
in the middle of a read you are probably going to get at least one 'bad
read' - ie rubbish byte, and this could be anywhere in the
program.......<br>
&nbsp;&nbsp;&nbsp; If you use the pic to do the switchover you should be able to
control when it occurs - ie have it complete all processes/interrupts
etc, suspend servicing any new ones, jump to a&nbsp; switchover routine
which can then achieve a clean switchover, then return to normal
operation.<br>
<br>
&nbsp;&nbsp;&nbsp; I am a hardware engineer, not a software guru, so the description
may be a bit simplistic, but I believe this approach should yield a
viable solution.<br>
<br>
Regards<br>
Bill<br>
<blockquote cite="mid20050211180159.0454537766 at ns2.nec.com.au"
 type="cite">
  <pre wrap="">

Message: 1
Date: Thu, 10 Feb 2005 18:46:31 -0500 (EST)
From: <a class="moz-txt-link-abbreviated" href="mailto:mbelloli at speedymotorsports.com">mbelloli at speedymotorsports.com</a>
Subject: [Diy_efi] Continuing the chip switcher problem
To: <a class="moz-txt-link-abbreviated" href="mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</a>
Message-ID:
	<a class="moz-txt-link-rfc2396E" href="mailto:4860.67.121.93.112.1108079191.squirrel at www.speedymotorsports.com">&lt;4860.67.121.93.112.1108079191.squirrel at www.speedymotorsports.com&gt;</a>
Content-Type: text/plain;charset=iso-8859-1

Hello Everyone,
     I had asked the question eariler in regards to creating a mulitple
bank chip switcher for an ecm.  Everyone basically said I should be
able to just switch the chip without any regard for whether the chip
is being accessed during the switch.  I finally got my pic chip
controller up and running.  I'm running at 20mhz, and when I do a
switch I'm still getting a check engine light.  2 out of three times.
 Thinking about this, I put the same exact bin in each of the banks
of the chip, and still get the same response.  Could it not be that
I'm switching in the middle of a read, and that is causing this
problem???  What does everyone think.  If I turn the car off, and do
the switch no problem.  I'm using this on a 1991 acura integra....had
a 27c256 as the base chip, and I'm using a 29c010 as the replacement.
 I'm controlling the highest two address lines as bank select for a
total of 4 banks.
     I'll put the info for chip changer on my webesite, and add a link to
it tonight.

     Any ideas???

Thanks,

Marcello


------------------------------

Message: 2
Date: Thu, 10 Feb 2005 18:57:41 -0500
From: David Cooley <a class="moz-txt-link-rfc2396E" href="mailto:n5xmt at bellsouth.net">&lt;n5xmt at bellsouth.net&gt;</a>
Subject: Re: [Diy_efi] Continuing the chip switcher problem
To: A list for Do-It-Yourself EFI <a class="moz-txt-link-rfc2396E" href="mailto:diy_efi at diy-efi.org">&lt;diy_efi at diy-efi.org&gt;</a>
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:1108079861.4995.6.camel at n5xmt.bellsouth.net">&lt;1108079861.4995.6.camel at n5xmt.bellsouth.net&gt;</a>
Content-Type: text/plain

I think it all depends on how the ECM is accessing the chip...
I know this wasn't a problem on GM's at least thru 95...


On Thu, 2005-02-10 at 18:46 -0500, <a class="moz-txt-link-abbreviated" href="mailto:mbelloli at speedymotorsports.com">mbelloli at speedymotorsports.com</a> wrote:
  </pre>
  <blockquote type="cite">
    <pre wrap="">Hello Everyone,
     I had asked the question eariler in regards to creating a mulitple
bank chip switcher for an ecm.  Everyone basically said I should be
able to just switch the chip without any regard for whether the chip
is being accessed during the switch.  I finally got my pic chip
controller up and running.  I'm running at 20mhz, and when I do a
switch I'm still getting a check engine light.  2 out of three times.
 Thinking about this, I put the same exact bin in each of the banks
of the chip, and still get the same response.  Could it not be that
I'm switching in the middle of a read, and that is causing this
problem???  What does everyone think.  If I turn the car off, and do
the switch no problem.  I'm using this on a 1991 acura integra....had
a 27c256 as the base chip, and I'm using a 29c010 as the replacement.
 I'm controlling the highest two address lines as bank select for a
total of 4 banks.
     I'll put the info for chip changer on my webesite, and add a link to
it tonight.

     Any ideas???

Thanks,

Marcello

_______________________________________________
diy_efi mailing list
<a class="moz-txt-link-abbreviated" href="mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</a>
<a class="moz-txt-link-freetext" href="http://lists.diy-efi.org/mailman/listinfo/diy_efi">http://lists.diy-efi.org/mailman/listinfo/diy_efi</a>
    </pre>
  </blockquote>
  <pre wrap=""><!---->

------------------------------

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diy_efi mailing list
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<a class="moz-txt-link-freetext" href="http://lists.diy-efi.org/mailman/listinfo/diy_efi">http://lists.diy-efi.org/mailman/listinfo/diy_efi</a>


End of diy_efi Digest, Vol 17, Issue 11
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