ALDL info

[Mark Glicksman]

Brian Hayes wrote:
> 
> I just got out some logic analyzer traces from my 86 Chev Cavalier - 4
> cyl.  This uses the 160 baud C3 - I assume.  Is it possible that there
> are only 8 bytes of data??? (plus the header).  The pattern seems to
> repeat every 81 bits ((8 data bytes + header byte) * 9 bits/byte).  This
> is the data I get:
> 
> Engine off - key on
> Byte Hex  dec
> 1    80   128
> 2    00     0
> 3    00     0
> 4    00     0
> 5    C9   201
> 6    00     0
> 7    76   118
> 8    00     0
> 
> Engine running - idle
> Byte Hex        dec
> 1    80 or 84   128 or 132
> 2    2A          42
> 3    00           0     MPH??
> 4    2B          43
> 5    B0         176
> 6    2A          42
> 7    92         146
> 8    2A          42
> 
> Byte 5 tends to decrease as the engine warms up (IACV??).
> 
> Bytes 2,4,6,8 always seem to be about the same.
> 
> The 9 1's are pretty easy to pick out in the header.
> 
> Any thoughts or ideas would be greatly appreciated.
> 
> ...The next step is to hook it back up and start pulling some wires!!

Hey Brian,

	This should be very good comparison data for when I start testing the
system I'm putting together.  I'llo let you know how it works out.

			VTY
			Mark Glicksman
			mglicksm at suffolk.lib.ny.us