[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>
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>
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.<br>
<br>
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"><4860.67.121.93.112.1108079191.squirrel at www.speedymotorsports.com></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"><n5xmt at bellsouth.net></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"><diy_efi at diy-efi.org></a>
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:1108079861.4995.6.camel at n5xmt.bellsouth.net"><1108079861.4995.6.camel at n5xmt.bellsouth.net></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=""><!---->
------------------------------
_______________________________________________
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>
End of diy_efi Digest, Vol 17, Issue 11
***************************************
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