ZeddyNet schematic

[mrtinb]

Hi

I see here http://forum.tlienhard.com/phpBB3/viewt ... =125#p5635 there's a schematic for ZeddyNet.

If I understand correctly the GAL is like a CPLD, just a lot of 74xx ICs combined into one chip.

Is there a schematic for the circuit inside the GAL as well?

[Paul]

The Zeddynet GAL equations should be in the same threads on tlienhard forums as well.
Its not secret
At the moment I am working on a new release without GAL replacing the GAL with a HCT138 and a HCT00.
Just wait a some weeks until the new board is released together with new Schematic.
If you would like to get a prototype board now then just PM me. Its definitely not the release version and has some flaws but it works without any modification, just not everything positioned as it should
Kind regards
Paul

[siggi]

Hi Martin
using this link

http://forum.tlienhard.com/phpBB3/viewt ... 616#p18802

you will find everything about ZeddyNet (software, hardware, GAL equations).

Have fun
Siggi

[mrtinb]

I found the GAL file in one of the previous posts.

Then I found a great easy to understand article about GALs, and their equation file format.

Now I see that the equation file you have made, is simply address decoding made with a single chip. I feel I've learned something great today.

[siggi]

No, it's not only address decoding, but also timing adaption from Z80 timing to WIZ812/W5100 timing requirements.

Siggi

[Paul]

I found the GAL file in one of the previous posts.

Then I found a great easy to understand article about GALs, and their equation file format.

Now I see that the equation file you have made, is simply address decoding made with a single chip. I feel I've learned something great today.

A thing to know about GAL usage:

The GAL is great as long as you are experimenting with decoding and timing etc. On the other hand its so small in capabilities that you should have bare TTLs in mind which are cheaper and should be used in the final "product"
As soon as it comes to many TTLs and board space becoms an issue, better go for CPLD directly because power consumption of GALs is rather high.

[sirmorris]

Also GALs are now pretty much an obsolete technology. They are just about still available but getting harder to obtain.

[mrtinb]

I found some cheap CPLDs Atf16v8b to play with. Are they also obsolete?

[sirmorris]

They appear to be.. http://www.microchip.com/wwwproducts/en/ATF16V8B

These are really good when you want to replace 3-4 TTL. They are compact, DIP, and pretty easy to use. Win win. The things you learn about these will prove a great stepping stone to the next level. The 16 refers to the number of I/Os. The 8 refers to the number of macrocells. The higher the number the more intricate you can make your logic.

[1024MAK]

I counter with ATF16V8C which are in stock with main steam electronic suppliers.

Does anyone know if these Microchip/Atmel "simple programmable logic device's" (SPLD) can be programmed on common programmers? As in has anyone tried?

Also, I am thinking of splitting the PLD talk into a separate thread.

Mark