Paul,

  With the Parallel Port, you are going through the super IO
  Chip.  This device is off the LPC (low pin count) bus.
  Four lines with multiplexing of command, address, and data
  bits.  From the LPC back into the system are a few more
  paths.  While the printer will generate an interrupt, that
  interrupt is polled to see if it is set.

  The BIOS is running a bunch of events in the background,
  with DOS sitting on top of that software.

  System is not deterministic.  So there is variable timing
  to the system on what the parallel port is serviced.

  There are ways of working around this, from both hardware
  and software points of view.  For hardware using a separate
  timing subsection to handle inputs from the eccentric shaft
  pulley, to software of rewriting the bios and coding
  everything in a fixed matter.  So it can be done.

  Nice thing about rotary engines is they are so much simpler
  to determine when to fire injectors, and spark plugs.  No
  camshaft timing required, so using the Ford Ignition
  subsystem for spark and DOS computer for fuel is very
  viable, that it should work nicely for the dyno testing.
  Once you have the parameters established, then code in that
  small micro controller for aviation use.  I still like
  redundant back up with 'Notlauf' (emergency run, aka limp
  home mode) which the 555 timer could provide.

  Tom W

  Good info Tom. Thanks. That explains why MTIMER is all over
  the playing field. I can buy a PCI plug in card with an external
  counter timer chip which may improve the situation. Also do
  you think a PCI plug in par. port card would help. I have one so
  I will try that.

  I have a listing around here someplace for the IBM BIOS.
  You would not happen to have it in computer readable form
  would you? How about a list of the back ground processes?
  I know time is lost to refresh the ram.

  Is there anything I can disable in the BIOS setting or config.sys?

  I don't think recoding the BIOS will work on these cheap mother boards
  as the ROM appears to be embedded  in one of just several chips
  on board. I might be able to live with it as is if I can get
  the RPM with a external counter timer chip.

  Thanks again for your thoughts on this thing.


------------------------------------------------------------------------
  http://www.via.com.tw/en/products/mainboards/others/p4pb_ultra.jsp

  I think I was wrong about changing the BIOS. It appears
  to be in flash. Perhaps they have a real time BIOS.

  There are two ways to update the BIOS:

  Second method:
  (System needs to boot into DOS prompt with bootable disk):

  1. Make a bootable system 3.5" diskette.
  2. Then copy the flash utility (eg. awfl818.exe) and the new BIOS file
  (eg. P4XBSOLI.BIN)
  onto this diskette. The latest BIOS update and flash utility can be
  downloaded from
  www.viavpsd.com for your specific product.
  3. Boot the computer using this diskette.
  4. At the A: prompt type awfl818.exe (file name).BIN.

  You can find out additional parameters of the flash program by type
  "awfl818/?". This will
  cause the flash utility to load and automatically use the new file.
  Just follow the
  prompts that you see on the screen. When you are through, reboot your
  computer. Please
  load the optimized default settings in the BIOS.

  WARNING!! During the final flash process, power should not be
  disconnected and the process
  should not be interrupted or the motherboard will not be able to boot
up.

  I am looking into this further.

  ---------------------------------------------------------------
  I have email into VIA. They make a whole range of PC boards for
  embedded applications. If every car had a PC the possibilities
  are stunning.

  http://www.via.com.tw/en/company/locations.jsp#usa

  BASIC is the fastest way to program. Programs can be written in
  minutes that take hours or days in C or assemble language.

  This mother board is 200 times!! TWO HUNDRED TIMES!!! faster than
  boards just ten years ago. BASIC historically has been dismissed
  as too slow for real time applications. NOT TRUE ANYMORE.
  DOS BASIC instructions execute in less than one microsecond.

  --------------------------------------------------------------------

  Wow! Look at this Tom.

  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  *==============VIA Flash Tool V0.9 Beta===============*
  *--------------       Readme      --------------------*
  *=====================================================*
  VIA Technologies Inc.

  *Description:
  This tool is used for flashing or backing up the BIOS under DOS on VIA
  VEPD Mother Boards with Award BIOS.

  *How to use:
  1. Execute "viaflash.exe" under DOS.
If you would like to show update status, please execute "viaflash
  /ps" instead.
  2. You will see the flash tool menu: (1) Backup BIOS (2)Update BIOS
Please enter the option that you would like to do.
  3. Key in valid file name:
If back up bios, please key in the file name for creating the file
  and saving the BIOS.
If update bios, please key in the file name for updating the BIOS.
Note: The empty file name is invalid.
Besides, please don't enter file name string the length of that is
  more than 8 characters due to DOS contriction; otherwise, we will just
  save the first eight characters.
  4. If update BIOs, please enter if you would like to update bootblock.

  5.The flash tool will show "Please Wait" and then "Programming Now"
  when flashing or backing up. When flash tool completed flashing or
  saving, you will see "BIOS Updated" or "BIOS Saved" on the screen.



  *Supporting ROM:
  SST= 49LF004B, 49LF040B, 49LF004A, 39SF020A
  PMC= PM49L004T
  +++++++++++++++++++++++++++++++++++++++++

  This is coming together real nice.

  Here is the block diagram for the board I have. It is
  a VIA EPIA-M. Tons of power and I/O for $80.
  I notice Intel is starting to build this
  kind of PC mother using the Atom processor.

  Paul Lamar

Hi Paul;

There are a ton of these boards being used in cars and mobile devices in
a wide variety of form factors.
For an open source BIOS replacement try:
  www.coreboot.org
VIA boards are well represented.
Some of the Intel Atom based boards may also suit your needs.

Also look up Texas Instruments OMAP.  One example is "Beagle Board".
These boot with U-boot / X-Loader and are typically Linux based.

Have fun!
Cary

Wow that is great Cary. I had no idea 3 seconds to Linux boot.
Wow this is great just what was looking for. The Holy Grail
of real time. Thanks for that URL.

BTW I got a PCI par. port working on the VIA card at B000 and I am about
to test it to see if the super I/O chip is slowing me down.

Paul Lamar


There is another Company you may want to check out....Linux OS,
extremely small, good expansion options.  Reasonably priced.

www.gumstix.com

Fran Losey

Thanks Fran.

------------------------------------------------------------

I decide not to modify the BIOS and stick with what every comes with
the mother board so any board will work. Also modifying the BIOS will
damage the board for running DOS PB development software.

I will just  off load the time critical stuff to a bit of hard ware.
 D to A can  output a zero to five volt signal that will control the
pulse width of four 555s driving injector transistors.

The RPM can be measured with a preloaded down counter triggered by
TDC on rotor one. Here is a preliminary schematic. Not shown is the
interface to the slide throttle position yet. None of these chips cost
over $2 bucks with the exception of the D to A.

Two bi di par. port cards are cheap at around $15 each.

What this means is the processor can read or write to these devices
any time it gets around to it.

DOS was designed for 3 par ports right from the get go.

Paul Lamar