128k multicart board (32 x 4k banks) questions

[universal2600]

Okay i'm in the process of making a 128k vcs multi-cart, with 32 4k banks, each selectable with dip switches, one is this board layout correct , and to clear a bit a confusion, to have bank 0 selected ALL upper/unused address bits (5 bits) are tied low, and bank 31 will have them all high? Plus when making the eeprom Image you'd take 32 4k images copy them with CMD into a 128 k image and write that to the chip?

board layouts are included and feel free to use if it works.

bottom layer:

 

16-32k:

 

 

top layer:

 

16-32k:

silkscreen, top, bottom layers:

 

16-32k:

 

component placement:

 

16-32k:

 

 

p.s the resistor is in the layout just too lazy to make new pictures

 

 

pcb layout (made in express pcb also includes 16 or 32k am27c128/256 board with ability to program through cart connector and extra header)

2600carts.zip

Edited October 23, 2016 by universal2600

[+5-11under]

Upper 5 address bits: sounds right to me.

32 ROM files: might be able to load separately in EPROM software (save when done). otherwise, if all files are exactly 4096 bytes, use copy /b, such as... copy /b file1.rom+file2.rom both.rom .

[universal2600]

Upper 5 address bits: sounds right to me.

32 ROM files: might be able to load separately in EPROM software (save when done). otherwise, if all files are exactly 4096 bytes, use copy /b, such as... copy /b file1.rom+file2.rom both.rom .

Thanks for clearing that up, so if I used to copy /b it will merge/combine the images in the order as was listed in the command aswell? Edited October 19, 2016 by universal2600

[+5-11under]

Thanks for clearing that up, so if I used to copy /b it will merge/combine the images in the order as was listed in the command aswell?

 

Yep, the files will be concatenated in the order listed. In my example, file1.rom would be at $0000.

[universal2600]

Yep, the files will be concatenated in the order listed. In my example, file1.rom would be at $0000.

Thanks, that clears up my (slight) confusion

 

P.s will using a 3904 to invert a12 work in this layout?

Edited October 19, 2016 by universal2600

[ZackAttack]

I think a 3904 will work if you have a pull-up resistor. Is there a schematic you can post too? It would be easier to review the circuit if you have a corresponding schematic.

[universal2600]

I think a 3904 will work if you have a pull-up resistor. Is there a schematic you can post too? It would be easier to review the circuit if you have a corresponding schematic.

 

don't have one at hand but I drew this based on the cart (not very complex imho) it's a bit quick and dirty btw,

 

[ZackAttack]

The schematic looks good to me, but it appears to be different than your first post. I count 6 resistors on the schematic, but only 5 on the component placement and PCB drawings. I probably am just overlooking something. You may might to double check though.

[universal2600]

The schematic looks good to me, but it appears to be different than your first post. I count 6 resistors on the schematic, but only 5 on the component placement and PCB drawings. I probably am just overlooking something. You may might to double check though.

i added the pull-up value to the transistor on the schematic just haven't updated the layout to accommodate it

Edited October 21, 2016 by universal2600

[ZackAttack]

 

Okay i'm in the process of making a 128k vcs multi-cart, with 32 4k banks, each selectable with dip switches, one is this board layout correct , and to clear a bit a confusion, to have bank 0 selected ALL upper/unused address bits (5 bits) are tied low, and bank 31 will have them all high? Plus when making the eeprom Image you'd take 32 4k images copy them with CMD into a 128 k image and write that to the chip?

 

board layouts are included and feel free to use if it works.

 

What reference did you use for the dimensions of the edge connector?

[universal2600]

What reference did you use for the dimensions of the edge connector?

pitch is .1 and I did verify by printing the layers and made sure board and pins met the correct measurements and does line up correctly with an

original PCB edge

Edited October 31, 2016 by universal2600