Now that the S100 bus XVGA video board (http://s100computers.com/My%20System%20Pages/VGA%20Board/VGA%20Board.htm)
has gone out to everybody, I would like to announce our next board…
It’s a V3 version of our tried and true SMB
(System monitor Board). The original board is described here:-
The following changes/updates have been
made to the board:-
The was a minor error on the above V2 board (pin
5 of U32), this is now corrected.
There was a report of the TMA 0-3 switch circuit
was not working reliably with the 80386 board at high speed, this circuit has
now been completely replaced/simplified with a single GAL.
An Intersil ICM7216D chip has been added along
with 3 new Digital displays to continuously display the frequency of the bus
master clock speed (PHI) in MHz.
A circuit and LED bar was added to continuously
display the bit pattern of a user defined output port. (default, LED Diagnostic
A circuit was added to trigger an interrupt if
the S100 bus ERROR* signal (pin 98) is activated.
A series of jumpers was added to easily attach a
logic probe cable (such as a USBee or Saleae unit) for hardware debugging.
The LM323K 5Volt, 3Amp regulator can be replaced
(in the same footprint/space) with a Pololu 5 Volt , 2.5 Amp D24V25 Switching
Almost all chips from the V2 board can be
re-used on the V3 board. Only the ICM7216D, 3 Digital displays and GAL 22V10 are
Please see the bottom of the above page for more
I will be sending off an order for final bare boards in the
next few days. If you would like one or
more boards please let me know (preferably by e-mail). The usual arrangements ~$15/board + postage
WHEN you get the board via PayPal.