1227748 PROM dumps

[Ludis Langens]

A while ago Steve Ravet asked for PROM dumps for the 1227748 ECM for the
2.5 L4 engine.  I've uploaded 13 to the incoming directory.  Two are for
the 1228321 ECM which uses the same circuit board as the '7748.  The
'7748 was originally used with the "R"/"U" and "K" engines.  I didn't
keep track of what vehicle some of the PROMs came from - they could be
any three of these.

1227748
  Program code @ $C008 (aka $4008): 72 ($48)
    ABLT6730.S19  1987 2.0 "K" auto 2000ppm
    ACMA9517.S19  auto 4000ppm
    ACMB9524.S19  auto 2000ppm
    ACMC9528.S19  auto 4000ppm
    ACMF9538.S19  1987-88 Fiero 2.5 "R" auto 2000ppm
    ACMH9544.S19  1987-88 Fiero 2.5 "R" stick 2000ppm
    ADSJ2829.S19  auto 4000ppm

  Program code: 72 ($48) w/alterations (bug fix?)
    ALWM6770.S19  1987-88 Fiero 2.5 "R" auto 2000ppm
    ANAM1667.S19  auto 4000ppm
    ATBS3453.S19  1987-88 Fiero 2.5 "R" stick 2000ppm

  Program code: 112 ($70)
    ATXD7724.S19  1991 2.2 "G"

1228321
  Program code: 80 ($50)
    ARRN7099.S19  1989 2.0 "1" auto 4000ppm
    ARRP7103.S19  1989 2.0 "1" auto 4000ppm

It looks like I've got a good poker hand forming in the ACMs and ARRs. 
Here's how the transmission and VSS options are selected:

Program code 72:
 $C244 (aka $4244) bit %10000000 : 0 == auto, 1 == stick
 $C246 (aka $4246) bit %00100000 : 0 == 2000 ppm, 1 == 4000 ppm

Program code 80:
 $C009 (aka $4009) bit %00000001 : 0 == auto, 1 == stick
 $C009 (aka $4009) bit %00001000 : 0 == 2000 ppm, 1 == 4000 ppm

The 2000ppm digital VSS signal (from the instrument cluster) is input on
WHITE-23.  The 4000ppm AC VSS sensor inputs at BLACK-6.  BLACK-13
grounds the other side of the VSS sensor.  When using an ECM connected
VSS sensor, the ECM outputs a 4000 ppm digital VSS on WHITE-22 and a
2000 ppm digital VSS on WHITE-3.

BTW, the 2000 ppm mode is only used in J-bodies (Sunbird, etc.) and
P-bodies (Fiero).  This means that the ACMB PROM must be from a J-body
('cause it's not on the list for a Fiero.)

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/