Re: Eagle CAD design and fabrication of C64 & Plus4 cartridges

From: Jim Brain <>
Date: Thu, 8 Dec 2016 22:12:39 -0600
Message-ID: <>
On 12/8/2016 7:24 PM, MindFlareRetro wrote:
> Not to step on any toes, but how are eBay sellers like Coprolite Computer
> By-Products pulling this off with their "Coprolite Mega-16 Cartridge
> Commodore 64 128 w/27C801 Eprom For 64 16k programs" ...
> <>
Not sure the question, but the design is simple:

the rotary switch picks 4 bits of the address, and the dip switches pick 
another 2.

The 2 diodes, and one of the little resistors create a wired 'OR' gate 
to select the ROM when eitehr ROML or ROMH are low.  The rest of the 
switches tie the 6 address lines high when the switches are not pulling 
them low.

Is this the design you'd prefer, one with switches for banking, and 16kB 
(it makes it a bit harder to use for 8kB images because you have to buy 
a 16kB EPROM , and you really need 1 more switch, on the GAME line, 
since that line should be high for 8kB ROMs.


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Received on 2016-12-09 05:00:02

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