ALDL, again

[steve ravet]

If you go the the diy_efi WWW page, click on oem systems, then click gm,
then click programming 101 you'll see in there a list of "units", which
is how to get from the binary value you see in an PROM (or aldl stream,
I suppose) to a real world unit like temp, rpm, mph, map, etc.  That may
help you decode the stream.

--steve

Padgett 0sirius wrote:
> 
> Well just a quick look at my Fiero (1227170/APR0164) ALDL (C3) gives a
> stream like this:
> 000 A4 00 2A 4D C5 00 38 3B 14 80 90 00 20 00 60 24
> 010 1A 87 90 01 4A 00 97 00 68 A0 00 2A 4B C5 00 37
> 020 34 14 80 8F 00 20 00 60 25 1A 88 90 01 4A 00 97
> 030 00 70 A0 00 2A 46 C5 00 36 33 14 80 8E 00 20 00
> 040 60 24 1A 88 90 01 4A 00 97 00 6E
> (then repeats for the next frame).
> 
> 00 2a (42) is the reported PROM ID. Diacom software interprets as follows:
> 
> Engine Speed................... 1275 RPM
> Vehicle Speed..................    0 MPH
> Coolant Temperature............  224 F
> Manifold Air Temperature.......  106 F
> Throttle Sensor Voltage........ 0.40 VDC
> MAP / Vacuum Sensor Voltage.... 1.08 VDC
> Oxygen Sensor Voltage..........  628 mV
> Oxygen Sensor Transitions......    1 #
> Battery Voltage................ 13.6 VDC
> Idle Air Position..............   70 #
> Injector Pulse Width...........  1.7 mS
> Spark Advance.................. 26.1 DEG
> EGR Duty Cycle.................    0 %
> Integrator.....................  128 #
> Block Learn Multiplier.........  144 #
> Closed Loop Status.............  Off
> Fuel Mixture Status............ Rich
> Battery Status................. Norm
> Torque Converter Clutch........  Off
> Park/Neutral Switch............  Off
> Power Steering Switch..........  Off
> EGR Diagnostic Switch..........  Off
> Learn Control..................  Off
> 
> Using available data, it seems likely that the "A0" at offset 019h (sorry,
> I find it easier to think in hex) is coolant temp (1.35*160-8), "33" at
> offset 039h is the RPM (1275/4=51/33h), & 46h at offset 035h is IAC (70).
> Suspect the rest can be decoded the same way once I get a chance to compare
> several readings.
> 
> Or is all of this common knowlege /way off ? Am trying to come back up to
> speed.
>         A. Padgett Peterson, P.E. Cybernetic Psychophysicist
>  Anti-Virus, Cryptographics, & Antique Radio Researcher
> http://www.freivald.org/~padgett/index.html
>  mailto:padgett at gdi.net     PGP 5.5 Key on request

-- 
Steve Ravet
ARM, INC
steve.ravet at arm.com
www.arm.com