Trying to understand Bank Switching Need info

[silverfox0786]

Hi I been reading up Kevin Hortons Bank Switch Document and understand a little of what is going on

 

what I wanted to ask though is this

 

Bank switch from what I understand resides in the actual Maskrom (Game Program)

 

so does this mean that all games made with only work with their respective style of Bank Switching

 

IE F8 wont work with say a Activision FE bankswitch

 

would the code need to be so its the same one used for the particular bankswitch used

 

 

Basically I ask this for the reason that I have 2 Tigervision games and these games don't come cheap, both carts are non workers and its the bank switch circuit that is broke most prob the Logic IC

 

so I was curious would I have to repair the whole cart with the 3F bank switch or could I use say an F8 standard 8K Bank switch circuit.

 

Thanks for any advice on this

 

 

[Rybags]

Bankswitching is needed because most old systems have a limit on how much ROM can be addressed within the cartridge space, and system-wide the limit was usually 64K so bankswitching is also used in a slightly different way on machines like the Atari 8-bit computers and C64.

 

It's like putting 10 pounds of shit into a 5 pound bag. At any given time you can "see" 5 pounds, and bankswitching is like taking some out and putting a different bit in.

 

For cartridges there's usually a fixed area that will always be the same (usually near the top since the system vectors are there) and a switchable area which will have anything from 2 or more banks.

 

The various systems in use, the number usually describes how the banking is performed, which in 2600s case is by accessing a particular address or range of addresses.

 

The chips - some ROMs were made such that the bankswitching logic is contained within the chip. In other cases, the banking might be performed by a seperate chip.

Generally if you want to create a real cart using a ROM image then it needs to be capable of the type of bankswitching which the original program used. In theory a program could be altered to work with another banking type but it's probably just easier to use the type it requires to begin with.

[silverfox0786]

thanks rybags that last paragraph was exactly the answer I was looking for