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How to hack cartridges

Posted: Mon Apr 30, 2007 5:25 am
by nbla000
I'm not an hardware expert so i try to explain:

I wish to reuse some unused cartridge, i want to remove the rom BLK/5 and replace a socket with a programmed eprom with some other programs for BLK/5, my questions are:

1) I may use any cartridge that use BLK/5 or just some model (example i may use Vic-Avenger but not Clowns because etc etc etc)

2) Which eprom i may use, only the 2732 eprom or may use other eproms too ? and where ?

3) Obviously i need an eprom burner which ? where ? cost ?

4) Which software is necessary to use the eprom burner and for which platform ? Vic/C64/Amiga/DOS/Win/Linux ?

5) My idea it's only a dream :( ? i hope it's not a dream :)

Thanks for any info

Re: How to hack cartridges

Posted: Mon Apr 30, 2007 6:37 am
by 6502dude
nbla000 wrote:I'm not an hardware expert so i try to explain:
I wish to reuse some unused cartridge, i want to remove the rom BLK/5 and replace a socket with a programmed eprom with some other programs for BLK/5, my questions are:


I had a post a couple of years ago on this topic.

nbla000 wrote:1) I may use any cartridge that use BLK/5 or just some model (example i may use Vic-Avenger but not Clowns because etc etc etc)


Most 4K & 8K cartridges may be hacked and game rom removed, a socket & eprom installed. There are a few exceptions where manufacturer didn't use a DIP chip and you will just find a chip with a blob of epoxy over it.

nbla000 wrote:2) Which eprom i may use, only the 2732 eprom or may use other eproms too ? and where ?


The cart ROM pinout matches 2532 eproms. However, this type was never as popular as the 2732 and you will have a challenge finding 2532 eproms. A simple wiring mod can be done to cart to allow you to use 2732 eproms. I think Schema did a diagram on this. I have a scan of a cart somewhere with the traces I cut and wiring to enable the 2732

nbla000 wrote:3) Obviously i need an eprom burner which ? where ? cost ?


Most modern eprom burners don't support eproms as small as 2732. E-bay is likely your best option.

nbla000 wrote:4) Which software is necessary to use the eprom burner and for which platform ? Vic/C64/Amiga/DOS/Win/Linux ?

This will be dependant on the eprom burner you buy. Promenade will work natively with Vic-20, C64, & C128. However, when these pop up on e-bay, they have been selling for very high prices.

nbla000 wrote:5) My idea it's only a dream :( ? i hope it's not a dream :)

It's not a dream - playing with eproms can be a lot of fun :)

Re: How to hack cartridges

Posted: Mon Apr 30, 2007 8:04 am
by Mike
6502dude wrote:I had a post a couple of years ago on this topic

I've found that post, sadly the pictures given in the link are no more accessible.
Most 4K & 8K cartridges may be hacked and game rom removed, a socket & eprom installed.

There is not much room over the EPROM if you install a socket, and you might need to cut a hole in the cartridge case.
The cart ROM pinout matches

... 2564 EPROMs. ;)
A simple wiring mod can be done to cart to allow you to use 2732 eproms. I think Schema did a diagram on this.

Yep, here it is. The most important thing is to cross A11 and A12. You can judge from the layout, whether your cartridge in charge can be used for the hack.
6502dude wrote:
nbla000 wrote:5) My idea it's only a dream :( ? i hope it's not a dream :)

It's not a dream - playing with eproms can be a lot of fun :)

Indeed. :D

Greetings,

Michael

Posted: Mon Apr 30, 2007 8:12 am
by nbla000
looking around the web i've found a lot of variant for 2732: 2732, 2732(A), 27C32,27C32A,27P32A all it's ok or i need a specific version ?
The eprom 2732 contain 32 kbits = 4 kbytes so for 8kbytes programs i need 2*2732 eprom, why not a 2764 ? the Schema diagram can be used for 2764 too ?

Re: How to hack cartridges

Posted: Mon Apr 30, 2007 8:16 am
by 6502dude
Mike wrote:
6502dude wrote:I had a post a couple of years ago on this topic

I've found that post, sadly the pictures given in the link are no more accessible.

I changed servers a couple of times since the orginal post.
I'll see if I can locate images again and put them back online.

However, Schema's drawing is much better than my ugly hack job

... 2564 EPROMs. ;)


I have only done this with 24 pin carts (4K). So, it's a 2532 pin out for me. :wink:.
A 2564 would be correct for 28 pin, 8K carts.

Posted: Mon Apr 30, 2007 8:25 am
by Mike
They all share the same pinout, but they differ in the voltage needed to program them.

Most EPROM burners, and their programs let you specify the exact type of EPROM you use, so you'd check the supported types there beforehand.
The eprom 2732 contain 32 kbits = 4 kbytes so for 8kbytes programs i need 2*2732 eprom, why not a 2764 ?

A 2732 has 24 pins, same as the 2564. Most of the pin-out of the 2732 corresponds to the 2564, and by swapping A11 and A12 you get the whole thing working. Opposed to that, a 2764 has 28 pins ... and some more pins to re-route, even if you'd use an intermediary socket.

Maybe it would be quite useful to make a 45mm x 90mm design, that specifically accommodates a 2764 EPROM. :roll: Any takers?

Michael

Posted: Mon Apr 30, 2007 8:25 am
by 6502dude
nbla000 wrote:looking around the web i've found a lot of variant for 2732: 2732, 2732(A), 27C32,27C32A,27P32A all it's ok or i need a specific version ?

The onces with "C" in middle of part number are CMOS vs. NMOS.

CMOS eproms generally use 12.5V programing voltage. The NMOS are typically 21V or 25V.

Most older programmers will allow either type to be programmed.

The eprom 2732 contain 32 kbits = 4 kbytes so for 8kbytes programs i need 2*2732 eprom, why not a 2764 ? the Schema diagram can be used for 2764 too ?


You need to match up Eprom size to the "host" cartridge. If it is a 4K game cart, then it will only have 24 pin chip. Thus, you can only fit in a 24 pin eprom (unless you want to drill extra holes and do more rewiring).

If you have an 8K game cart as "host" for the project, it will have a 28 pin rom and you can fit an 8K eprom (such as 2564 or 2764).

Posted: Mon Apr 30, 2007 8:34 am
by carlsson
I bought a True Willem USB programmer a few weeks ago. It supports 2716, 2732, 2764 and upwards. I have a bunch of the following EPROMs:

TMS2516 (identical to 2716), TMS2532 (different pinout)
various branded 2732, 2764, 27128, 27C256, 27C512 and so on

I also have a couple of unpopulated Datatronic VIC-20 cartridge boards, as used in their editions of e.g. Jelly Monsters, Avenger and most other Handic releases. I don't know if true Commodore cartridges use these boards.

These boards have two EPROM slots, and I've verified they work with 2516/2716 or 2732. However I believe I've seen one of these boards fitted with a 2532 too, without any special wiring?!? Is it even possible that the cartridge would accept both 2532 and 2732 in the same slot? Unfortunately, the True Willem does not support 2532 natively, and I haven't wired myself an adapter to program one.

The USB programmers are a bit expensive, around $80+ plus shipping. If you can live with a parallel port programmer (one of the older Willem designs or some completely different one) you can probably get away with $25-30 plus shipping on eBay, or the same amounts but in Euro if you prefer to buy from an European dealer instead of Canada, USA, China, Taiwan, Thailand etc.

Posted: Mon Apr 30, 2007 8:48 am
by nbla000
wow, i didn't think that there was much interest on this thread ?

yes there was a lot of programmer for 2732/2764 and relatively cheap too i've discovered some 2564 eproms too but 28 not 24 pin :?: here there is a the 2564 pinout and here the 2764 pinout, seems that both use 28 pin. :?:

Re: How to hack cartridges

Posted: Mon Apr 30, 2007 9:01 am
by Mike
6502dude wrote:I have only done this with 24 pin carts (4K). So, it's a 2532 pin out for me. :wink:. A 2564 would be correct for 28 pin, 8K carts.

What the heck! :evil:

I somehow meant the 2564 was pin-compatible to the 24-pin ROM, but it doesn't even have 24 pins. :oops:

I must have confused it with the 2364, the latter which is pin-compatible to the 24-pin chips used in the cartridges, but it is only a PROM chip.

I've found the MCM 68764 after a short search, but it seems to be a seldom used, and rather expensive part.

2732 and 2532 differ in their pins 19..21.

Michael

Posted: Mon Apr 30, 2007 9:40 am
by nbla000
6502dude wrote:If you have an 8K game cart as "host" for the project, it will have a 28 pin rom and you can fit an 8K eprom (such as 2564 or 2764).


ok but since it's possible to find 2564 eproms but not burners how may adapt 2764 eproms to cartridge that use 2564 eproms ? there are cartridges that use 2764 eproms ? 2564/2574 eproms in original cartridges are erasable by UV ?

Code: Select all

     2564                         2764             
      +----o----+                  +----o----+       
  Vpp | 1     28| Vcc            1 |Vpp   Vcc| 28   
 /CS1 | 2     27| /CS2           2 |A12  /pgm| 27   
   A7 | 3     26| Vcc            3 |A7     nc| 26   
   A6 | 4     25| A8             4 |A6     A8| 25   
   A5 | 5     24| A9             5 |A5     A9| 24   
   A4 | 6     23| A12            6 |A4    A11| 23   
   A3 | 7     22| PD/PGM         7 |A3    /OE| 22   
   A2 | 8     21| A10            8 |A2    A10| 21   
   A1 | 9     20| A11            9 |A1    /CE| 20   
   A0 |10     19| D7            10 |A0     D7| 19   
   D0 |11     18| D6            11 |D0     D6| 18   
   D1 |12     17| D5            12 |D1     D5| 17   
   D2 |13     16| D4            13 |D2     D4| 16   
  Vss |14     15| D3            14 |Vss    D3| 15   
      +---------+                  +---------+       


modify to do 2564 --> 2764 ?

2  -->  20?
20 -->  23
22 -->  27 ? PD ?
23 -->  2
26 -->  28?
27 -->  20?
[/code]

Posted: Mon Apr 30, 2007 10:50 am
by carlsson
Are you sure the cartridge uses 2564? Regarding 68764, I think Schema had (or may still have) a small supply, but it requires your burner to be able to handle this chip. I'm wondering if it is not easier to design a cartridge board from scratch, using 2764 EPROMs.

Posted: Wed May 02, 2007 5:01 am
by nbla000
I've opened a lot of cartridges, most cbm cartridges but not all have the Schema's layout and use a different MOS chip for each cartridge, the Atari cartridges use 2 chip labeled 2364 (24 pin - 8k x BLK5 AND 1 OR 2 OR 3), Creative cartridges use a very complicated layout with another chip 24 pin, no any cartridge use a chip with 28 pin, so my conclusion is that without hard hacks you may reuse only some cbm cartridges adapting a 2732 eprom for BLK5 ($a000) but with 4K programs only (some cartridge or my PRG2CART conversions)

Posted: Wed May 02, 2007 6:18 am
by 6502dude
Good detective work on the carts.

I have only pulled about a half dozen apart over the years.

If I have a chance over next few days, I'll go through my collect and see what I come up with.

One option on the ones that use the 2364 though, is to use a socket adapter and a 2764 eprom.

Posted: Wed May 02, 2007 8:05 am
by nbla000
I think it's a little bit harder to find this 2364->2764 adapter though seems to be easy to do but in any case what i think is:
Since a lot of cbm carts use an 8k rom and these roms are all of 24 pin may be that this roms are 2364 labelled by commodore with own part number, may be ? there is a way to check ?

2364->2764 adapter layout:
Image