95 LT1 PCM (16188051) uses a 16202476 MCU !!

[Tom Hussey]

Hi,

I am sure the 16202476 processor is a MC68HC11F1. All the I/O port
addresses line up with the data sheet. I can see from my disassembly of
the '97 Camaro that the SPI port is manipulated on both processors for
redundancy and how the data comm scheme works. Other chips I have
identified are MC68HC58 for OBDII data comm, mc33291 or mc33298 for
octal drivers. I have decoded the section that drives these chips.
Anyone with part numbers? Flash used is 512K on event side and 64K on
the timing side.
The OBD chip is at $1060 and $1061 if anyone is interested.

-Tom


Ken Kelly wrote:
> 
> Ludis,
> 
>         Do you know which Variant of the HC11 this is?
> 
>         The original posting was to try to identify which variety
> of 68HC11 is in the 16202476? We are disassembling the 8051
> EEprom, and the memory maps are different in the different
> variants. We thought it was a 68HC11K4, but David Cooley,
> thought that it was a 68HC11F1. Davids comments were based
> on a P6 and I need to look at my board tonight, but I seem
> to remember seeing P5 in the silkscreening.
> 
>                 Ken
> 
> Ludis Langens wrote:
> >
> > "David A. Cooley" wrote:
> > >
> > > I have 2 unidentifiable chips, 52 pin PLCC's, one is 56597 and
> labeled
> > > Delco, the other is labeled NCR and is 129170
> >
> > The ECM for the '95 2.2 L4 "4", 16191947, also uses a 16202476 and a
> > 56597.  The 16191947  uses a MEMCAL with a 27_512.  I assume the
> 56597
> > is a two injector version of the buffer / I/O port / peak+hold
> > controller which all the P4's use.
> >
> > Check the circuitry around the 56597.  Are there two diodes, two
> 1.8K
> > resistors, and two polarized capacitors, all hooked together and to
> two
> > pins of the 56597?  The old single injector controller uses these
> parts
> > to implement a voltage doubler.
> >
> > Other chips in the 16191947 are:
> >      34987  O2 amp
> >      34992  Power supply
> >      34993  IAC driver
> >   16045152  CD4011 quad NAND (?)
> >      45153  CD4051 mux (?)
> >      64606  ALDL interface
> >      04891  ???
> >      89551  ???
> >   16132083  ???
> >   16206550  ???
> >
> > --
> > Ludis Langens                               ludis (at) cruzers (dot)
> com
> > Mac, Fiero, & engine controller goodies:
> http://www.cruzers.com/~ludis/