Multicart information

[pmpddytim]

I'm interested in multicarts. This is mostly personal curiosity becasue I believe they are beyond my skill level (and probably comprehension) but I would like to read up on how they work, and how they are made. What are some good sources for reading material?

 

-Tim

[Susuwatari]

Here?

 

You wire up the cart as normal except the higher address lines are connected to switches to select banks of ROM.

 

Switches are usually DIP switch and one side are connected to ground (or V+, it doesn't matter) while the other side goes to the address line of the EPROM. Then there are a series of resistor from each of the address to V+ to pull up the address when the switch is not closed (resistor to ground if the switch itself is connected to V+)

 

To make the ROM image, collect the individual ROMs you wanted to put on, and use the copy command to combine multiple fille into a single large image. Make sure the whole image is of correct size and then burn it to an EPROM.

[pmpddytim]

Thanks! I was never quite sure how those things worked and did not want to spend the money just to take one apart. I was not sure if it was a lot of seperate eproms, just one, or what.

 

Thanks again, and sorry for the kinda dumb question.

 

-Tim

[Susuwatari]

You could use EPROM up to 8Meg (I don't think there are any 8-bit EPROM bigger than 8Meg that are easily obtained cheap) but beyond that, you may need to mess with multiple EPROMs. The easiest way to select specific ERPROM is via /E line (not the same as /CE line used with 2600 A12 line and hex inmverter) This puts the EPROM instandby mode with output in high impedance so it shouldn't interfere with other EPROM.