68HC705V12

[FJB203 at aol.com]

In a message dated 97-04-10 14:07:14 EDT, you write:

> Has anyone had any experience with the 68HC705V12.  Apparently its meant to
>  be a dedicated dashboard chip, with a number of lines for sensors and
direct
>  driving of gauges.  I'm currently thinking of doing a digital dash and
>  happened to come across an article on this chip.  I'm just asking to find
>  out if anyone has any good or bad experiences with this chip.

I designed a six digital "analog bar graph" gauge dashboard, complete with
large 199 mph speedometer, mileage (including 10ths) that will easily attach
to either a parallel port on a PC, or to a 68HC11E9 (or other microprocessor
that has a 8-bit parallel port output).  I haven't built it, however you are
more than welcome to take a look at it.  Its in autocad's DXF format, and
unfortunately, too large to convert to a GIF or JPEG, at least with the
crappy shareware I have.

I didn't do a Tach yet...

Basically, I took the 8 bits and divided them into two 4-bit nybbles, the
high order nybble being the "gauge select" and the low order nybble being the
graph value, which the electronics then latch and will hold the display.  I
intended to use red rectangular LEDs for the "warning" areas of the graphs,
Green for the "okay" areas, and blue or yellow rectangular LEDs to indicate
the center and endpoints of each graph so they mean something.  This is just
a display circuit, the microprocessor would have the responsibility and
required programming to convert an analog signal (i.e. oil pressure) to what
the guage will display from end to end.

Fred