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Posted By

on 2018-02-17
 universal cartridge quick guide

I have been asked by many people if I could do a quick guide to using the Coprolite Computer By-products universal cartridge board.
So here is the projects so far that I have come up with:
On the blue board I ran a trace from pin 20 of (socket 1) to pin 20 of (socket 2) BUT I forgot to run a trace from Ground to pin 20.
A jumper wire is required to fix that.
(on the purple board I corrected that issue and no jumper is needed)

If you are setting the board to use a cartridge image that only uses 1 eprom (single 16k),for example (JACK ATTACK)
(1)the eprom will go in location 1 and
(2) solder jumper R1 and R2.

If you are setting the board to use a cartridge image that uses 2 eproms (dual 16k),for example (SCRIPT/PLUS)
(1) the eproms will go in location 1 & 2 and
(2)solder jumper R1 and R2.
Ok that should take care of a SINGLE progran in 1 and 2 slots.

But wait there is more:
Now if you want to use a 27256 (32K) eprom and put 2 different programs on the cartridge and switch between the 2
that is simple, all you have to do is:
(1) Add a resistor to location R1, I use a (10K) (0805) only because I ordered a roll of 5000 of them and
(2) put a single dip switch on (bank A),
this will allow you to switch between the 2 different programs.
But lets say you want to do more:

How about if you want to use a 27512 64K eprom and put 4 different programs on the cartridge and switch between the 4?
Well then what you need to do is:
(1)put resistors on R1 and R2 and
(2)use a dual dipswitch
this will allow you to switch between the 4 different programs.

ok and the last thing , the reset button...
Just solder it in place ........ and YES I know the system already has a reset built in so no need to tell me it is redundant,
I added it because I wanted to.

I am including pictures as guides to show you exactly what I mean by any above instructions plus all this information will also be included on our FB page under Coprolite Computer By-products

Proud supporter of CRX, Commodore Retro eXpo

Posted By

on 2018-02-17
 Re: universal cartridge quick guide


1. Does this only support $8000-BFFF address space (16k ROM), or does it support $8000-FFFF (a single 32k ROM)?

2. It seems that most every configuration requires that R1 and R2 be soldered. Is there a configuration that does NOT require them to be soldered? Or are the resistors (for 64k of ROMS) the reason these are not already soldered?

3. Can these boards be purchased from you, with R1 and R2 already soldered? Will a later revision have them jumpered already (like the jumpers in a 1541-style drive), to where a user can scratch out the connection instead?

4. For those of us not on Facebook, do you have a website where we might get more information, prices, and possibly place an order? (An order link could be as simple as a mailto link, I'm not asking for a full shopping cart.)

Posted By

on 2018-02-17
 Re: universal cartridge quick guide

ah some very good questions ....
I opened a c-16 tutor cartridge and just did a full copy of what c= had done then added the 2 resistors one to pin 27 and one to pin 1 and added the dipswitches, so I would guess 16k only
as I do not have a 32k image to try
with R1 and R2 yes they always get soldered with jumpers or resistors
I sort of left it up to the end user to decide
but in any case R1 and R2 can have resistors installed no matter what eprom is used

I have the blue boards listed on eby, soldered up for use with 1 16k eprom, including the eprom
and the purple boards are listed as bare boards
I am willing to do what ever soldering someone may need me to do
but my off ebay prices is WAY cheaper
as for FB I do not have a FB account , I refuse to ......
its the wife that set it up and maintains it
people can get ahold of me here
or on skype at the same addy

Posted By

on 2018-02-17
 Re: universal cartridge quick guide

There aren't many 32k ROMS in the Plus/4 universe ... but this site has a few, such as an odd version of Three-Plus-One. Its the single file at the bottom of the download links:

I ask because it's not difficult to join two 16k ROMS into one EPROM ... if we could join the two halves of Script/Plus into one ROM, and the two halves of Calc/Plus into another ROM, then we could have two 32k cartridges on your board.

The last I looked, Ebay took about 9% of the selling prices for themselves, and PayPal another 2.9% plus 30 cents. If you are willing to sell off-Ebay, yet still invoice through PayPal (for buyer and seller protection), some of us may want to take advantage of your offers.

Facebook -
Ebay US -

Posted By

on 2018-02-18
 Re: universal cartridge quick guide

I will play with that and see if I can get it built into the next board order
it can't be that hard, I did it on the c64 system
but as it is now the cart can hold (Script/Plus) and (Calc/Plus) with 2 27256 eproms
if you wanted to add 2 more for a total of 4 programs just use 2 27512's
it just takes the use of 2 eproms instead of 1 , just like the original cart
one of the pictures shows how to do the (SCRIPT/PLUS)

I have no issues at all doing PP invoices, doing it that way I can easily print a shipping label
bare boards can be shipped first class letter, assembled boards need to go as first class package due to thickness

Posted By

on 2018-02-18
 Re: universal cartridge quick guide

well I got up and made a pot of coffee
spent 2 min looking at the pin-outs of the cart port
then took a few min to do a very ugly hideous looking hack
took the Three-Plus-One images low and hi , combined them and burnt a single 27256
and it does work, but I must say the hack is ugly
I will work it in on the next run of boards
I keep toying with using a 27801 next time around , but I do not think I will ever find 1 meg worth of cart
here is a pic of the abomination

Posted By

on 2018-02-18
 Re: universal cartridge quick guide

For clarification: I am not asking if your board will support four 32k ROMS (or two 64k ROMS).

All I would like to know, is if I can have a 32k ROM in the left socket, and a different 32k ROM in the right socket, and the Plus/4 be able to see *either* the left or right ROM as one continuous ROM (depending whether the left or right ROM is switched in at the time).

From what you said a few minutes ago, with the single Three-Plus-One ROM ... your boards currently do not support what I ask, you will look into this possibility for the next batch. Am I reading your response correctly?

Posted By

on 2018-02-18
 Re: universal cartridge quick guide

Very nice project, I really like the details given. "abomination" LOL

Too sad we do not have enough CRT/ROM files to load with a bigger EPROM, just because very few released.

a little OFF:
BTW it is too complicated to create from a single file 16K or 64K game a CRT/ROM file?
I mean if you check the Games Top20 there are several single file piece even from the newer ones, not to mention the classics. (Mercenary, Laser Squad2 Onefile, Head Over Heels, SpyVSSpy3 (Bag), etc )
Could be there will be more interest to have a "Best of Games" cartridge, than an (othwerwise really impressive) Easycalc, youwill never use in real life, next to Excel or SVS Calc ( )?

Posted By

on 2018-02-18
 Re: universal cartridge quick guide

JamesC ok I see what you are saying
and no the board is not set to handle 1 program on the bank low rom (1) location and a 2nd different program on the bank hi rom (2) location
you would need to put both programs on the same eprom at the rom low (1) location and use the dipswitch to select the program you wanted
but what you are saying is possible with a few trace cuts and some Frankenstein wires added
then all that would happen is you would select rom 1 or rom 2 with a switch

MMS thank you
about converting games to crt , I am not a coder, and would have no clue where to Begin
I am 100% strictly only hardware

Posted By

on 2018-02-19
 Re: universal cartridge quick guide

Hi Ken,

Noted, and fully understand. I know what you mean, I am 90% graphics, and lame in everything else
(even in GFX I need some development ).

Posted By

on 2018-03-06
 Re: universal cartridge quick guide

I took your idea of a single 32k and drew it up , so the cart can do 16k /32k or 4 16k's or 2 32k's on a single eprom
then I said to myself....what do I do will all that empty board space
so I added 2 41464's and 2 24LS257's ....A project for the c16 I have had in the works for 2 years for now

Posted By

on 2018-03-07
 Re: universal cartridge quick guide

I've seen requests on this forum for memory expansion. Good job, hopefully some of the people who posted before will notice this.

Now, a silly question: can your memory be used as additional memory (like a ramdrive), or does yours completely override the built-in memory?

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