Need help with this interface I bought

[BrunoFlorindo]

I've bought several TS1000 items on eBay, one of them being described like this:

"1 - zebra systems (disc?) interface - this has an 8bit A/D converter chip on it and also DIN connectors. The DIN connectors are the same as on a C64 Floppy disc connector."

Since I'm not a wirehead, I wouldn't know what to do with this interface. I can take pictures of it and may even ship it to someone who could study it, reverse engineer it and shared the schematics with everyone before returning it to me.

While I wait for the interface, can someone give me an idea of what this interface might be used for?

I e-mailed Mr. Stewart, the co-owner of Zebra Systems, but his reply was similar to the auction description. Maybe he doesn't remember. Anyway, I didn't want to insist.

Thanks in advance.

[Littlejohn]

The best ting to do, is when you get it, take good quality pictures of the front/back. Then post them somewhere, or Email them to me and I will host them for you, so everyone can get a good look at them and go from there.

[BrunoFlorindo]

Thanks! Here are the pictures:















Components that I was able to identify:

ADC0809CCN - analog to digital converter
74LS27 - Triple 3-input Positive NOR Gate

By the way, I received several interesting items today. I will also take pictures of these so that everyone can see them. One of the items is a Bus Expander very similar to the one you did for the Apple 2.

[Math123]

HI Bruno,

this board is nothing more or less than a multiple input A/D converter. And the two connectors are for the analog inputs.
Now you will be able to interface two or more analog joysticks.
Not bad at all.
Matthias

[BrunoFlorindo]

Hi Matthias.

Ok, so I could connect analog joysticks to the interface, but:

-How do I determine which ports or addresses have to be used?
-If the chip is an 8-channel a/d converter, how to I determine which pins are being used in each socket? The total of pins is 12 (and the socket is nothing I've ever seen)
-Since most joysticks use DB-9 connectors, I assume I have to build a custom cable, correct?

I was reading the datasheet for the ADC0809CCN and it seems this interface could prove really useful to ZX81 users.

[Math123]

Hi Bruno,
do you have some better pictures of the complete board? To understand the adress-wiring we have to look at the underside of the edge-connector.
I see something strange at the pins of the 74LS27. Is there some damage at the solderside?

As far as I understand the board and the specs of the a/d chip you only have to perform input instructions on different adresses to get the analog values of the 8 channels.

You are right. You need some special wiring. Do you have the special plugs? Or would you prefer to solder some different cables to the board? There is a DIL structure prepared to do so.

Is there more interesting hardware you got?
Tell us more..
Matthias

[BrunoFlorindo]

Hi Bruno,
do you have some better pictures of the complete board? To understand the adress-wiring we have to look at the underside of the edge-connector.

Hmm, not sure what that means. Do you mean the bottom of the interface, or the part where the lines end and connect to the edge connector?

I see something strange at the pins of the 74LS27. Is there some damage at the solderside?

I'm not sure if it's damaged, but only have of the pins are really soldered. The 74LS27 is secure, though.

As far as I understand the board and the specs of the a/d chip you only have to perform input instructions on different adresses to get the analog values of the 8 channels.

And this is where I get confused. I'm really in my first baby steps towards the electronics world, so here it goes: I learned that these type of chips only decode a certain memory range. I also read somewhere that some ZX81 a/d interfaces worked with POKE and PEEK, while others used machine code to read ports. But on this one I have no idea where I should start (I only know Basic, btw).

You are right. You need some special wiring. Do you have the special plugs? Or would you prefer to solder some different cables to the board? There is a DIL structure prepared to do so.

A DIL structure? Could you tell me more about it? The interface came with one plug for it, but no cable, meaning that I have to figure out the wiring by myself. But all isn't lost. The good news is that I found out what this interface was meant for. It was designed so that ZX81 users could use the Koala pad, a peripheral that was very popular among Apple II and C64 users. So there you go. The gentleman who contacted me by e-mail also told me it can be used to add a mouse or joystick to the ZX81. Really nice! I'm waiting to see if I can find more information about this.

Is there more interesting hardware you got?
Tell us more..
Matthias

I think I have a few more things that might be of interest to some, but I haven't had the time to take pictures. I do plan to take pictures of everything, especially what's hard to find, so that everyone can see it, learn what it does, and maybe find a way to build it if desired. I don't want to keep things for myself.

May I ask a favor? I see there are many, many interesting hardware projects at the german ZX81 forum. Is there any chance some users from over there could come to this forum and share the knowledge and maybe some ideas with us? It would be great. By using English we can reach a lot more ZX81 users.

[Math123]

Hi Bruno,
I think the best would be to have some better pics to see the complete board.
As I can say so far this board only uses machinecode I/O reads on different adresses.
So just send or post a picture of the complete board. (with visible wiring of the edgeconnector).
Then I can give you all the details and maybe some helping machinecode to get data out of the board.

Concerning the german forum...
Have you ever tried the Google translator?
This would be a first aid here. And then I would try to simply ask the german guys in english all the questions left.
If there will be problems in communication there will be somebody to help with translations.

Language is still a barrier,
Matthias

[BrunoFlorindo]

Oh my... my old free host is gone...
I still need help with this interface. As soon as I find it I'll send it to Spain to a good friend of mine. I'm sure we will find out how it works.