John, One board for me please.
Ian > On May 31, 2015, at 1:53 PM, monahanz <[email protected]> wrote: > > I would like to now introduce what will probably be the final version of our > very reliable S100 16MB Static RAM board. > It’s called the V5 16MB Static RAM S100 board. See here:- > http://s100computers.com/My%20System%20Pages/16M%20RAM%20Board/16MG%20RAM%20Board.htm#A_Third_Prototype_16MB_Static_RAM_Board > > <http://s100computers.com/My%20System%20Pages/16M%20RAM%20Board/16MG%20RAM%20Board.htm#A_Third_Prototype_16MB_Static_RAM_Board> > (Bottom of the page). > > This board has the following additional features:- > > I did not want to change the basic RAM board circuit. It has proven itself > time and again to be very reliable with any CPU board I could throw at it. > Common easy to obtain 74LSxx chips are used throughout. > I wanted to hand lay down broad power traces to all the boards IC’s for more > even power distribution. > I have inserted a trace “Keep out Area” on the front of the board so there is > no danger of the 5V and 3.3V regulator heat sinks touching a critical trace > beneath. > I added two 22V10 GALs to replace a number of 74LSxx chips. This greatly > simplifies the board and somewhat speeds up the RAM access times. I realize > not everybody is familiar with GAL’s. For those people who cannot program > GALs and beginners ,I will supply the pre-programmed Lattice 22V10 GALs. The > PALASM code is provided on the web page. These GAL’s are fairly common > (Jameco #39159 for the 15ns variety). > 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. > People should be able to simply switch IC’s from the old board to this new > one. Two new GAL ICs is the only major change. > While the board is really built to meet the 16MB addressing range of the > IEEE-696 bus, I have added jumper options so the board can be used in older > systems like an Altair or IMSAI which only use a 16 bit address bus. > Altair/IMASAI RAM write protect/unprotect can also be implemented on this > board. > The board can accommodate EITHER the dual Mezzanine RAM boards described > above (V6.0c), for 16MB of static RAM, or 8MB by soldering the 4 SMD > CY62167DV30 static RAM chips directly on the board or 16M, by soldering 4 of > the newer SMD AS6C3216 (4M X 8bit) static RAM chips on the board. > Last but least, I relabeled much of the Silk Screen to be more relevant. For > example placing IC numbers above their pin locations etc. > > Anyway I will do a group order for a batch of these V5 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. > > It’s best to send me an e-mail direct (monahan AT vitasoft DOT org). > > John > > > -- > 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] > <mailto:[email protected]>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. > --- > > Filter service subscribers can train this email as spam or not-spam here > <http://my.email-as.net/spamham/cgi-bin/learn.pl?messageid=281E5D8207D711E5B529A66993ED0201> -- 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.
