FW: Re: Project update (long)

[Ciciora Steve]

  In message <9409010858.ZM1446 at montreal> , you write:

I'm not prepared to make specifications yet, but... here's what I had in
mind.

- +5VDC +/-5% at 2A max continuous (0mA min)
- +/-15VDC +/- 10% at 0.5A 
- input 8-16VDC w/the spikes and dropouts associated with the starter running.
- industrial temperature range (no internal ventilation; i.e., no external air
vented into the case)
- short circuit protected
- power on diagnostics that will not turn-on the outputs unless voltages are
within tolerance. (what can we do to prevent damage to the rest of the
circuit in the event of a supply failure?)
- notify cpu of "power off" condition (see next item).
- supply power for say 0.1 sec after input power is removed.
- shutdown command from cpu.
- LED indicators for +5VDC, +15VDC, -15VDC, and input power.
- power-on lamp test function for the above.
- external voltage (load voltage) sensing
- must be able to reverse the polarity of the input supply without damage.
- turn-on to output voltages within tolerance delay of less than 0.3 sec.

  Wow, I'm not sure I want to see the specs when you _do_ have a chance to
think about it!  After you build yourself one, can you build me one? :-)  What
I'm doing for now is to take a 12V DC to 120V AC inverter and run some lambda
switching power supplies off of it.  I even run my old 8Mhz '286 off of it
(don't have a laptop... yet).  I found a bunch of surplus compaqu 12V DC EGA
monochrome monitors for $5.  Anyway, I'm getting carried away.
  Do you really need to have it supply power for about 0.1 sec?  I was planing
on having the computer powered all the time, and can enter a low-current
shutdown mode.  Or at least the power supply always on.  Or wait, how about
this:  The ignition switch turns on the power supply, and when the key turns
the car off, the computer does it's shut down routines, and then the computer
shuts off the power supply.
  Guss What!  I'm getting a REAL C compiler for the 6811!  In exchange, I have
to write a few simple programs for the group next door...  While I know other
CPUs would be better suited for this project, I'm now very committed to the
6811.
-Steven Ciciora