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TI 99/4A Eprom Cartridge
#1
Recently, I built a 8K eprom cartridge to use the >6000 space available at the cartridge slot.
This space can be used for multiple purposes. You can clone a rare Rom based cartridge or write your own.
This project uses a spare TI Invaders cartridge, though there are a few others that will work as well.
If a socket is used on the board, different cartridge roms can be exchanged on the board to change applications easily. There are also 4 Grom spaces available, these can also have sockets installed and will allow up to a possible 4 more titles on the menu along with the eprom at >6000
It appears groms have internal pre-assigned addresses so some will conflict with each other.
What's needed: a 2764 eprom(s) , a TI Invaders cartridge, optional sockets and either a eprom programmer, or a friend with one, along with soldering and desoldering skills and the necessary equipment to do it.
Dumps of Rom only cartridges are available online.

I created a PDF to help a fellow TI er build one, that I can make available here if possible. Otherwise, PM me and I'll send it to you.
* I did upload the pdf, it's attached to a message after this one.
Steve


Attached Files Thumbnail(s)
           
#2
Steve, this is an interesting project from the standpoint of re-utilization of old cartridge boards. If you want to build larger cartridges, there are also other options. The Gerbers for the 64K bank-switched Guidry boards are available online, as are the Gerbers for the 512K variant that gives 4 128K bank-switched zones selectable by a pair of switches on the case. These two use the DataBioTics inverted switching method. For non-inverted switching, you can use the 512K boards I recently finished--or you can use one of the Über-GROM boards designed by Jon Guidry, Tursi, and I. Those should be available to the community at large in the very near future.

It is always good to see other people doing neat hardware experiments on the TI--and you can also find a lot of what is happening in the hardware world over on AtariAge in their TI subforum.

Jim

(04-15-2014, 06:43 PM)sjt99 Wrote: Recently, I built a 8K eprom cartridge to use the >6000 space available at the cartridge slot.
This space can be used for multiple purposes. You can clone a rare Rom based cartridge or write your own.
This project uses a spare TI Invaders cartridge, though there are a few others that will work as well.
If a socket is used on the board, different cartridge roms can be exchanged on the board to change applications easily. There are also 4 Grom spaces available, these can also have sockets installed and will allow up to 4 more titles on the menu along with the eprom at >6000
What's needed: a 2764 eprom(s) , a TI Invaders cartridge, optional sockets and either a eprom programmer, or a friend with one, along with soldering and desoldering skills and the necessary equipment to do it.
Dumps of Rom only cartridges are available online.

I created a PDF to help a fellow TI er build one, that I can make available here if possible. Otherwise, PM me and I'll send it to you.

Steve
Enter my mind at your own risk!
#3
I have a few Romox cartridges with sockets installed. I've only used SRAM because I don't yet have an EPROM burner.
#4
Ksarul

I had heard there were new boards that had been developed, but couldn't find availability or pricing.
I had extra duplicate cartridges, which was a quick almost free source of boards to experiment with.
How are multiple 8k rom cartridge bin files prepared so they can be software bank switched.

Barry,
I assume you obviously have added a cell battery to preserve the code in the static ram?
I actually don't own a Romox , curious what the board looks like.
Shoot a few pictures if you get a moment. (both sides)
If you compress them you can upload them here or pm me and I'll give you an email address.

How do you load the Sram
#5
The 8K files have to be set up using a menu program loaded into the first and last bank of the cartridge image you're building (first and last because the chips that control the bank switching can initialize in either of those banks at random). The cartridge boards were sold as part of two large group orders (16K and 64K Guidry boards), on the CodeHackCreate website (64K Guidry boards) and made as short-run additional boards (64K Guidry boards) by several individuals. The only current source for the larger boards (512K types) is me. I do have a small number of the last batch of 512K non-inverted boards (bare boards) left.

(04-15-2014, 10:50 PM)sjt99 Wrote: Ksarul

I had heard there were new boards that had been developed, but couldn't find availability or pricing.
I had extra duplicate cartridges, which was a quick almost free source of boards to experiment with.
How are multiple 8k rom cartridge bin files prepared so they can be software bank switched.

Enter my mind at your own risk!
#6
(04-16-2014, 07:29 AM)ksarul Wrote: The 8K files have to be set up using a menu program loaded into the first and last bank of the cartridge image you're building (first and last because the chips that control the bank switching can initialize in either of those banks at random). The cartridge boards were sold as part of two large group orders (16K and 64K Guidry boards), on the CodeHackCreate website (64K Guidry boards) and made as short-run additional boards (64K Guidry boards) by several individuals. The only current source for the larger boards (512K types) is me. I do have a small number of the last batch of 512K non-inverted boards (bare boards) left.

(04-15-2014, 10:50 PM)sjt99 Wrote: Ksarul

I had heard there were new boards that had been developed, but couldn't find availability or pricing.
I had extra duplicate cartridges, which was a quick almost free source of boards to experiment with.
How are multiple 8k rom cartridge bin files prepared so they can be software bank switched.


For those interested in knowing more about the layout of the TI cartridges, and would like to experiment with one. I'm uploading a pdf (soon to be revised a bit) that will help.
It also details how to convert a TI invaders cartridge into an eprom cartridge.


Attached Files
.pdf   buildepromcart2.pdf (Size: 2.4 MB / Downloads: 55)
#7
(04-15-2014, 10:50 PM)sjt99 Wrote: Barry,
I assume you obviously have added a cell battery to preserve the code in the static ram?
I actually don't own a Romox , curious what the board looks like.
Shoot a few pictures if you get a moment. (both sides)
If you compress them you can upload them here or pm me and I'll give you an email address.

How do you load the Sram

No battery, I've not spent much time with it/them. I loaded the contents via the HRD menu program. (I think)

I'll make a picture or two when I find one. It should be very easy to duplicate.
#8
(04-17-2014, 12:27 PM)barryp Wrote:
(04-15-2014, 10:50 PM)sjt99 Wrote: Barry,
I assume you obviously have added a cell battery to preserve the code in the static ram?
I actually don't own a Romox , curious what the board looks like.
Shoot a few pictures if you get a moment. (both sides)
If you compress them you can upload them here or pm me and I'll give you an email address.

How do you load the Sram

No battery, I've not spent much time with it/them. I loaded the contents via the HRD menu program. (I think)

I'll make a picture or two when I find one. It should be very easy to duplicate.



Yes, when you can. I would appreciate seeing it.
Check your archives ...on what you used with it.
I'll check and see if I can find any info on it.

Thanks.

BTW I uploaded a file detailing how the TI cartridges are setup, especially the TI Invaders board.
#9
Hello Steve, i build your project very usefully work.. an info you had create a list of original rom that one can use in your 8k board? i tested ti invader and obvious no work (miss the grom chip!) i looked in pics cars war is working? you tested another grom?
Bye Ermanno
P.s. a end of November show in Florence computer fair your speech work :-)
#10
Hi
Glad you had fun making a eprom cartridge.

When I have time, I was thinking of making an update, so you can add a larger eprom and use it as a multicart.

On which 8k files will work, I will see if I have a more complete list.

On groms you can include along with your eprom, this gets a little tricky. Groms have unique addresses. So they can't conflict.
A game/cartridge that is a grom 1,2,3... etc only will work. Another can not have the same grom addresses.
So a game that is grom1 and another that is 2&3 will work, and come up on the menu.
The problem is knowing what the groms are. There are cartridge dumps for gram cracker and the gram card that will help identify which can work together.

BTW I just visited Florence a few weeks ago, along with Venice , Lake Como, Pisa, and Rome.

Steve


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