The reason I bring it up is that your dumper could be modified in a simmular way were the software automaticly flip flops between its ROM and the cartrage.
That would be possible, although designing such a circuit it's beyond my basic skills. It would be a bankswitching logic just like those used in games, switching between the software eprom and the cart instead of two different banks of the same rom. To work with the dumper it would need a couple of features:
1 - The "hotspot" address must not be in cart space, because the dumper needs to read the entire cart address range
2 - The hotspot must not interfere with those used by other bankswitch methods that use TIA or RIOT addresses (such as "3F" used in Tigervision carts).
3 - The dumper rom must always be selected when powering the console.
A less elegant but simplier way would be to use a pin of a controller port as a select line and connect it to the dumper through a cable. Once connected to a controller port, you can have also the rs232 adapter and connector built into the dumper itself. The software already implemets a select line on an unused pin of the RIOT chip, to be used in case someone want to install the dumper inside a console (see the first post). Using a controller port would allow the auto-switching even with an external device.
I haven't checked yet, but I think that it would be quite easy to modify the software to support this feature.
This is the simple circuit I intended to use when I added the auto-select function in the software. It uses a 74HCT00 (quad NAND gates). I haven't tested it.
Note that it only uses 3 of the NAND gates. There's another one on a 74HCT00 and it can be used to invert the /CE signal in case you use a second cart programmed with the dumper software instead of an eprom built into the device itself.
Edited by alex_79, Mon Sep 19, 2011 3:09 PM.