[Gmecm] Sunbird/$58 ALDL protocol

[Robin Handley]

Hey Bill,

I think you're dead right about the timing sensitivity. I'm really surprised
that GM made the $58 code behave differently from the $8D, though. My
current $58 test program waits until it sees the $BB checkum of the chatter
message and immediately after sends a request for Mode 1 data - which the
$58 responds to with data, and the chatter message is inhibited for a few
seconds. It seems that, if the Mode 1 request doesn't come out at just the
right time, it is ignored and the chatter messages just churn out. That
isn't the case with $8D. The weird thing is that, with my test program, the
$58 code gives me the Mode 1 data 3 times consecutively from my program
start and then ignores subsequent requests! If I stop and restart my program
it does the same again. This sounds like a bug in my program, but I tried
the program with ANHT/$8D and it worked fine! I know the $58 should work
repeatedly because, once locked on, ALDLMON works. This is really confusing
me ATM! :-)

BTW: Yes, the Turbo P4 doc is the one I was referring to. Following what it
describes, I've been testing the Mode 4 ability to turn the fan on, like I
did for ANHT/$8D, and having problems with that too, using $58! I expected
it to work straight away! :-(

BR,

Robin

----- Original Message -----
From: "Bill Shaw" <b.shaw at comcast.net>
To: <gmecm at diy-efi.org>
Sent: 04 June 2006 16:29
Subject: Re: [Gmecm] Sunbird/$58 ALDL protocol


> Hi Robin,
>
> The $58 code is very timing sensitive.  It's been a while since I've
played
> with it so the details are a bit fuzzy,  but as I remember you have to
send
> a mode change within a couple hundred milliseconds of the 'chatter' packet
> to get it to shut up and start taking commands.  Once you change mode
it'll
> respond OK to your commands until it times out aned returns to 'chatter'
> mode.  Do you have the Turbo-P4 doc?  It's spelled out pretty well in
there,
> look for 'turbo_p4' or something like that on incoming.
>
> Best,
>
> Bill
>
> > From: "Robin Handley" <Robin at FuryWorld.fsnet.co.uk>
> > Reply-To: gmecm at diy-efi.org
> > Date: Sun, 4 Jun 2006 15:45:12 +0100
> > To: <gmecm at diy-efi.org>
> > Subject: [Gmecm] Sunbird/$58 ALDL protocol
> >
> > I've noticed different behaviour on ALDL between ANHT/$8D and
Sunbird/$58
> > code in my '727. The ANHT/$8D seems to behave more
'sensibly/predictably.'
> > than the Sunbird/$58 code!
> >
> > I'm currently trying to find a robust algorithm to talk to the
Sunbird/$58
> > code. I have modified ALDLMON (which works but takes longer to lock on
than
> > it does with ANHT/$8D) and played around with some noddy programs of my
own
> > (not w/o some issues, which I'm still trying to get to the bottom of).
Has
> > anybody played with ALDL from Sunbird/$58? The code chucks out $F0 $55
$BB
> > repeatedly. The Turbo code doc. indicates that the ALDL monitor should
> > reply, but does not appear to say with what. Anybody know what the
correct
> > response is?
> >
> > Robin
> >
> > _______________________________________________
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