View Full Version : Update on the S-100 PC To ASCII Converter Board

February 10th, 2010, 12:47 AM
Andrew and I have finished our S-100 PC Keyboard to ASCII Converter
board we mentioned a few weeks back on this site. I have written a
detailed account here if you would like to find out more about the
board see here:-


The initial batch of manufactured boards has been all spoken for. If
there is sufficient interest we can make a second batch.

February 10th, 2010, 08:00 AM
Hi! Thanks John!

This has been a challenging and fun project. The board itself is really interesting and an enjoyable to watch. I think this board would make restoration of legacy S-100 systems especially those with parallel ASCII keyboard interfaces a *lot* easier. Especially since it blends in with the rest of the S-100 system it would make a nice addition to anyone's restored S-100 computer.

I have mostly built up my own board and done some testing. As soon as I get the rest of the parts it should be ready to go. My plan is to adapt it to my Vector Graphic clone with FlashWriter II video and parallel ASCII keyboard interface. Currently I am using a kludged parallel ASCII keyboard much like the one at the top right hand side of your webpage.

IMO the main problem with it is the parallel ASCII keyboard is "naked" and has no case. It also required a small translator PCB to convert the signals. As a result it is rather delicate with wires floating about. I think it would be a big improvement to use a cheap PS/2 keyboard and save the real parallel ASCII keyboard for other projects. The PS/2 keyboards are better suited for the workshop since they are cheap and plentiful. They are fairly well self contained and resistance from saw dust, wire clippings, etc.

Thanks and have a nice day!

Andrew Lynch

February 10th, 2010, 10:14 AM
Hi! I'd like to especially thank the hobbyists who have bought the first round of the S-100 keyboard and S-100 IDE boards. It is a brave person who will purchase the first release of any product -- especially home brew electronics. You are making these home brew computer projects possible by spreading the risk out to a tolerable level.

If we are ever going to get to more, better, and different S-100 (or any kind for that matter) home brew boards have to get past the first generation or two to shake out the problems. S100Computers.com and/or N8VEM developed home brew computers and/or boards are different from a commercial venture -- there is *no* R&D department. Those all important first adopters are paving the way for everyone to benefit by allowing us to make the boards without going broke in the process. THANK YOU!

I recognize the first batch of PCBs are basically prototypes so "cuts and jumpers" are not unusual. As much as John and I try to make the boards completely 100% right the first time in reality some errors are going to escape. Anyone experienced with S-100 systems and/or home brew computers are familiar with "cuts and jumpers" even though we try our best to prevent them. I appreciate your patience with us as we work through the issues!

There are a couple S-100 related projects in work. The next project is the S-100 SRAM/EPROM board. We've ordered and received prototype PCBs to work out the remaining kinks on the design before making a PCB manufacturing order. Hopefully this new approach will improve first time quality.

After the S-100 SRAM/EPROM board, we've got a S-100 Front Panel project. The schematic and PCB layout is done and I have a prototype PCB in autorouter optimization. We'll get prototype PCBs for it too. The S-100 Front Panel is a two part design. There will be a board that plugs into the S-100 bus for interface and logic and another mezzanine board with the displays and switches.

I would like to make some additional PCB manufacturing runs of the S-100 boards depending on hobbyist demand. So far there are five completed designs; S-100 backplane, S-100 prototyping board, S-100 buffered prototyping board, S-100 IDE, S-100 keyboard. The IDE and keyboard designs could probably use a respin but work fine with minor corrections.

Thanks and have a nice day!

Andrew Lynch

February 18th, 2010, 09:03 AM
Hi! I received the parts to almost finish my S-100 keyboard project. I still need to build a cable to hook up a PS/2 keyboard and some configuration adjustments. However the testing of the board so far has been very positive and the board seems to work fine. I like the LED displays (HP5082s and bar LEDs) and this is a fun board to work with.

The PCB definitely needs a respin although it works fine with the minor corrections. As soon as there is enough interest for another batch I will make a PCB manufacturing order. There has been some interest although not enough yet to warrant a new order. Hopefully that will happen soon although it is OK if we wait a while so I can catch up on other projects.

Thanks and have a nice day!

Andrew Lynch

February 22nd, 2010, 08:50 AM
Hi! A quick update on this project. Yesterday afternoon I finally got all the parts and time to put it together. It works great in my Vector Graphic clone S-100 system with FlashWriter II video board. The PS/2 keyboard connects to the S-100 keyboard board which in turn connects to the FW II parallel ASCII keyboard interface. It really works slick and the status LEDs are really nice.

I removed the HP5082 displays for use on another project and am using the LED bars for status as the board works. You can see the data flowing in and out of the board. There are many LEDs and a system buzzer for audio feedback. The only thing remaining to do is make a better cable between the S-100 keyboard board and the FWII since I broke my 24 pin IDC socket connector.

The board itself is pretty easy to make and the software worked the first time. I am thinking about making some customizations like keyboard true reset signal and enabling the bell with the FWII.

Just follow the instructions on S100Computers.com S-100 keyboard page and you can assemble the board fairly quickly. You'll need to make your own cable to interface to your video board and that is pretty easy. I made mine for the FWII and it worked the first time. John has one for the SD VDB 8024 although I am sure any parallel ASCII keyboard interface would work. Basically they are all variations of 8 data bits, strobe, ground, and maybe optional signals like acknowledge, reset, bell, etc.

Thanks and have a nice day!

Andrew Lynch

PS, if there is enough interest for another batch of manufactured PCBs I will respin the PCB to fix the minor issues requiring jumpers. So far there has been some interest but not enough yet to warrant another PCB order.