[Diy_efi] Continuing the chip switcher problem

[Martin E]

Marcello,

As an electrical engineer, I would say that it would  be wise to Latch your
bank switching bits on the rising edge of the read strobe. This way the
address will not change during a READ (usually active low). Ugly things will
happen and you may not meet the setup and hold times for the Flash memory.
Also if the bank switching wires are 'long' you may be coupling in noise to
the ECM, as well as switch bounce noise.

cheers
Martin

----- Original Message ----- 
From: <mbelloli at speedymotorsports.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, February 10, 2005 6:46 PM
Subject: [Diy_efi] Continuing the chip switcher problem


> 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
>
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>


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