Denial

Attached are my Vic-20 Cartridge Eagle PCB design files for clones of the Commodore 8K and 16K designs. These have been produced and fully tested. They fit the original Commodore cases and aftermarket cases. I am releasing these to make it easier for people to make custom cartridges. These files are ready to produce by submitting them to a PCB shop. I used DirtyPCBs online shop ( http://dirtypcbs.com/store/pcbs ).

Materials needed:
PCB (see below zip file for EAGLE PCB files)
EPROM - 2764 for 8K carts or 27128 for 16K
.1 uf ceramic capacitor
ONLY 16K board requires - 7400 or 7437 Quad NAND gate/buffer logic chip (S,LS, etc. fine also)
Optional:
Case - 3D printed https://www.thingiverse.com/thing:2697596 or third party seller (google search)

INFO:
The 8k PCB is pre-selected to use BLOCK 5. It can be changed by scraping off the bridge between the selection pads and soldering a bridge at the desired location marked on the board. The 16K is pre-selected for BLOCK 5 and BLOCK 3. These can be changed in the same manner. The 16K bin file should be created with low address-high address.

3D printed case shown The specifications for ordering the boards are:
Size: Max 10X10mm
Thickness: 1.6mm
Material: FR4
Layers: 2
Quantity : Protopack±10 (recommended)
Coating: HASL OR ENIG (gold)
Color: Your Choice
Copper: 1oz OR 2oz
Stencil: None

Ordering Instructions for dirtypcbs.com: (I'm in no way affiliated with them, just used them in the past - you may choose another vendor)

Simply select the .BRD file you wish to have made using the included photos in the zip file below as reference and upload to http://dirtypcbs.com/store/pcbs using the CHOOSE FILE button. Then set the parameters as shown above. Now press the ADD TO CART button. The cart will appear and after a moment, a small rendering of the selected PCB will appear in the upper left. Press the LAYER REPORT button and it will take you to a larger rendering where you may review it in more detail. If all looks good, close that window. Once at the cart again you can checkout. The lower priced shipping options can take awhile, so use them only if you aren't in a rush.

I recommend using the panelized versions for the best value for your money. The break apart easily and require no removal of material because it was accounted for in the design.
Any issues with the silk screen shown in the produced prototypes were corrected.

8K Panel 16K Panel Single 8K Single 16K The files I released are PUBLIC DOMAIN. You may do with them as you wish, including modifying, selling, etc. The only reason I even did this is because no public domain designs were available. I encourage more people to release public domain designs to help keep this platform alive. Please use these files as you see fit. The VIC-20 seems to suffer from a lack of custom cartridge homebrews. I'm just trying to make it easier for people to create custom carts who may not want to take the time and effort learn how to make low cost PCBS. These can be ordered just as easily as ordering anything online using the information above.

Files:

Having some fun experimenting with 3D printed cases and homemade labels. Jelly monsters came out dark because I used Glow-In-the-Dark paint on the label. BEHR-BONZ I bought on here and made the case.

It was brought to my attention that the 16K files had some 5 mil min clearances that are smaller than the 6 mil limit some board producers want. Attach is an updated file with 8 mil minimum clearances. The old file in the first post has also been replaced.

Thank you this will come in handy.

No problem you're welcome. One thing I forgot to mention is that you can use either a 7400 Quad NAND gate or a 7437 Quad NAND buffer on the 16K board. I have tested both and either one works fine.

norm8332 wrote:No problem you're welcome. One thing I forgot to mention is that you can use either a 7400 Quad NAND gate or a 7437 Quad NAND buffer on the 16K board. I have tested both and either one works fine.

Do you have a schematic picture of the 16k board ?

I'd like to know if I can mod it to use DRL logic instead of a 74 series logic chip.

It is an almost direct clone of the Commodore design. I did not do a schematic, it was just adapted for a 27128. Their design uses NAND gates. I always thought you could only do AND or OR without transistors. I do know that if you replace the chip with 4 copies of the below schematic it will work.

norm8332 wrote:It is an almost direct clone of the Commodore design. I did not do a schematic, it was just adapted for a 27128. Their design uses NAND gates. I always thought you could only do AND or OR without transistors.

All you need is AND and OR. The 7400 design uses a NAND gate to combine Block_H and Block_L and another gate with both inputs tied to invert the result, feed the output to pins 20 and 22 of the 27128. Feed Block_L directly to A13...

This board is wired to get the 7400 to act as a single AND gate (and probably a buffer too). It's much simpler to use 2 diodes and 1 resistor (at a few pennies each) to do the same thing but you're not giving me the missing details I need.

I do know that if you replace the chip with 4 copies of the below schematic it will work.

Now, you absolutely, positively don't need that!

All you need is ONE single AND gate.

If that's true I wonder why Commodore didn't do it that way? Maybe they had a ton of stock to get rid of or something.

If you download the eagle files above you would have all the information that I have on the design and you easily could derive what you are seeking from that. A schematic was never done because I just copied the design directly from a Voodoo Castle cart while switching the wiring to a 27128. If you would like to create a schematic, by all means please do. You could use Eagle free ( https://www.autodesk.com/products/eagle/free-download ) or Fritzing ( http://fritzing.org/download/?donation=0 ) etc.

FWIW I got the logic chips on ebay at 17¢ each shipped.

TO ALL: The files I released above are PUBLIC DOMAIN. You may do with them as you wish, including modifying, selling, etc. The only reason I even did this is because no public domain designs were available. I encourage more people to release public domain designs to help keep this platform alive. Please use these files as you see fit. The VIC-20 seems to suffer from a lack of custom cartridge homebrews. I'm just trying to make it easier for people to create custom carts who may not want to take the time and effort learn how to make low cost PCBS. These can be ordered just as easily as ordering anything online using the information in the first post.

Norm

If that's true I wonder why Commodore didn't do it that way? Maybe they had a ton of stock to get rid of or something.

two possible reasons:
1) they can produce the ICs themselves and then they are very cheap
2) ICs could be machine picked/placed and soldered - that makes the production cheaper

Seems plausible.

The First post has been updated with more detail on how to order these from DirtyPCBS for persons that need more clarity in the ordering process.
I also added a list of materials.

I am in no way affiliated with DirtyPCBS. I just have used them myself, and have always had a good experience. Also their website takes the eagle .brd files directly which makes it easier because Gerber files don't have to be exported.

norm8332 wrote:If that's true I wonder why Commodore didn't do it that way? Maybe they had a ton of stock to get rid of or something.

Commodore made boards by the millions. Even if the parts would have been cheaper by using a pair of diodes and a resistor, it would have increased their workmanship bill. For them using a logic IC was a better decision.

If you download the eagle files above you would have all the information that I have on the design and you easily could derive what you are seeking from that. A schematic was never done because I just copied the design directly from a Voodoo Castle cart while switching the wiring to a 27128. If you would like to create a schematic, by all means please do. You could use Eagle free ( https://www.autodesk.com/products/eagle/free-download ) or Fritzing ( http://fritzing.org/download/?donation=0 ) etc.

Just having a good picture which clearly shows the traces on both the top and bottom side would be considerably simpler than installing a new software.

Could you provide these, please ?

Floopy wrote:

Yes! I can see!

Awrite...

The 74_00 can be replaced with:

- A jumper between pins 9 and 11
- a Schottky diode between pins 1 (cathode) and 6 (anode)
- a Schottky diode between pins 2 (cathode) and 6 (anode)
- a resistor of 2.2kOhms between pins 5 and 6

Exactly the same trick I used on the Behr-Bonz to create one missing gate.