John, I would like one of these boards.
Thanks! - Alex On Saturday, May 16, 2015, monahanz <[email protected]> wrote: > It's hard to believe but this board is now over 5 years old. It is > probably our most popular S100 bus board to date. It went through two > major revisions. > > I would like to now introduce what will probably be the final version of > this very useful S100 board. It’s called the V3 IDE/CF Card S100 board. The > main updates are:- > > - > > I did not want to change the basic 8255 driven circuit and all the > software I and others have over the years written for the board. Sure > if I were to do it all over again I would probably have done it different > using perhaps a faster Zilog PIO or an onboard fast fully dedicated Z80 (as > for our ZFDC board) or Propeller etc. The NEC or OKI 82C55-2’s are > dirt common and seem to be able to handle anything the CPU sends to them. > - > > I want to hand lay down broad power traces to all the boards IC’s for > more even power distribution – particularly to the power hungry HEX > displays. > - > > I have inserted a trace “Keep out Area” on the front of the board so > there is no danger of the IDE adaptors touching a critical trace. > - > > I have now switched to a “multi regular” voltage regulator footprint. This > allows you to use either:- a 1.5Amp L7805CV, a TO-3 LM323K (3Amps), > a Pololu 5 Volt , 2.5 Amp D24V25, or a EzSBC.com 3A regulator > called PSU5. > - > > I did bend the *no new changes* rules a little and added two 22V10 > GALs. This greatly simplifies the board and really speeds up the port > addressing and the potential drive select/reset issues some were having. > I realize not everybody is familiar with GAL’s. Please see here for > more information about GALs. For those people and beginners I will supply > the pre-programmed Lattice 22V10 GALs. The PALASM code is shown below. > Again these GAL’s are fairly common (Jameco #39159 for the 15ns > variety). > - > > Correct a potential drive A: or B: switch circuit problem described by > some. > - > > I have added a wait state circuit (0 - 8 I/O wait states) to > accommodate very fast S100 boards such as our 80386 and 80486 boards > without requiring further generalized I/O wait states on the CPU board for > other system I/O ports. > - > > People should be able to simply switch IC’s from their old board to > this new one. Only two new GAL ICs and two 74LS373 are required. > - > > Last but least I relabeled much of the Silk Screen to be more > relevant. For example placing IC numbers above their pin locations etc. > > > > > I have written up a description of the board here:- > > > > *http://s100computers.com/My%20System%20Pages/IDE%20Board/My%20IDE%20Card.htm* > > <http://s100computers.com/My%20System%20Pages/IDE%20Board/My%20IDE%20Card.htm> > > (Bottom of the page). > > > > This time I had 4 final productions boards made by PCBCart (China) > before I announced it. That way I don’t have to worry about a large batch > of boards coming back with a critical design flaw. The picture on the > web site is the final board, not a prototype. > > > > Anyway I will do a group order for a batch of these V3 bare boards. > Please > let me know ASAP if you would like one or more bare boards. They will run > somewhere between $14 - $16 each + shipping. Note batches of these > boards do/will not occur often. If you even think you will need such > a board, now is the time. > > It’s best to send me an e-mail direct (monahan AT vitasoft DOT org). > > > > John Monahan > > -- > You received this message because you are subscribed to the Google Groups > "N8VEM-S100" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <javascript:_e(%7B%7D,'cvml','n8vem-s100%[email protected]');> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
