Character Generator Tester

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Character Generator Tester
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PDF icon Schematics482.91 KB
PDF icon BOM112.39 KB
File Short movie25.82 MB
PDF icon Popular Electronics April 1974 article673.28 KB

Last year I developed an ASCII Keyboard Tester (see https://www.applefritter.com/content/ascii-keyboard-tester and https://www.applefritter.com/content/ascii-keyboard-tester-pcb-and-kits) to please my curiosity in the electronic workings of the Apple-1. Great to see this scene of enthusiasts is so alive.

I came across an article by Don Lancaster in the Popular Electronics April 1974 issue about the ASCII Keyboard and Encoder. They use a Monsanto MAN-2 display, a 5x7 dot matrix. Using a 2513 character generator, it displays a single character that is typed in on the ASCII Keyboard. It is on page 29/30, some PDFs around there are missing these specific pages, so I attached the article here for reference.

Anyway long story short, I designed a Character Generator Tester, which shows the characters that are generated by the 2513. I use a KingBright TA-07-11EWA as a display. It also supports 2316B, 2716 EPROM and 2816 EEPROMs. So it enables you to test Character Generator’s for the Apple-1 and Apple ][, and you can test self made EEPROMS (or 2513 drop-in’s) that should replace the originals.

It uses a clock with stepping function and speed adjust. So you can see the row address counting and how the display is being built up. It also has LEDs that show the 6-bit ASCII input to the character generator. It uses the same power supply connector and DIP-16 keyboard connectors as the ASCII Keyboard Tester, the -5V is generated on-board. I also added an 8-bit counter output to feed for example the ASCII Keyboard Tester or other experiments, I needed the binary counter anyway for the display.

I tested it with Signetics 2513N from date 7703, a RO-3-2513 out of a ITT 2020 (early 79) and a 341-0036 (2316B) out of an Apple Europlus. Works great, but I was unable to test the (E)EPROMS yet, I assume they will work as they have the same pinout as the 2316B?

The design was a lot of fun, coming from a software background, I am learning a lot of electronics. Schematics and BOM is attached, let me know what you think about it. Kits are coming up as well.

 

 

 

 

 

Regards from Holland,

 

Bobby

 

 

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That's pretty nifty! 

That's pretty nifty!

 

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I like it. Congratulations on

I like it. Congratulations on the work.

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That's great, although also

That's great, although also maybe a little overkill I really want one!!

I didn't check, but thought easier to ask... are the board files attached or available project through one of the big suppliers?

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jeff d wrote:That's great,
jeff d wrote:

That's great, although also maybe a little overkill I really want one!!

I didn't check, but thought easier to ask... are the board files attached or available project through one of the big suppliers?

If a KiCAD project or at least the Gerbers file is posted then anyone can easily order boards from JLCPCB or PCBWay or a few other places.

 

That'd be super sweet.  I'd probably not be able to resist building some.

 

A sort of related project, this one is software, which I have used to view .bin files before burning them to EPROMs is here in my GitHub:

 

https://github.com/softwarejanitor/chargen2png

 

It should work on Linux as long as you have Perl and Perl-Gtk installed.  It probably will work on MacOS too if you install those using Brew and CPAN.  Windows I have no idea since I don't have or use Windows, but I imagine it might work with Strrawberry Perl or something.  I don't know and have no way to test it.

 

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I like to keep this hobby

I like to keep this hobby affordable for me, so for now I offer PCBs and Kits in the sale and trade section, see: https://www.applefritter.com/content/character-generator-tester-pcb-and-kits

Any questions please let me know, also open for 'reseller' interests.

 

 

 

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That is a terrific value-add

That is a terrific value-add KBD tester.  Very nice work indeed!

 

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