I have a game that I am wanting to put on a board, but I do not have a TKROM game to use, only a TSROM. I noticed that you can add a battery to a TSROM game (Like said here ---->
http://www.nesreproductions.com/mapper4b.html ) But I can not find instructions on how to do this? Can someone shed a little info on this subject =) Its a custom game that I edited that I am trying to get working. Thank you
I think the battery would just parallel the 5V+ power supply to the RAM. Maybe a diode to isolate the battery from the power supply. There might also be a connection from the MMC3 to the RAM chip for saving? There are lots of cheap TKROM boards on eBay though.
Here you are the official way to connect a battery (used in licenced cartridges).
Material needed :
- 2 diodes (lowest forward voltage is the better)
- 2 resistors (1 kiloohm)
- 1 capacity (2.2 microfarad) (optional, but recommanded)
- 1 battery (obviously)
Power suply (VCC) of RAM connected in parallel with the capacity (polarized correctly) to the cathode of the two diodes.
The first diode goes directly to VCC, the segond diode connects to the positive born of the battery trough the 1 kiloohm resistor.
The last resistor must go from the positive CE line to ground, so that when the MMC isn't powered, the line is effectively to ground.
Early SNROM boards (revisions 02 and 03) does lack the capacity and the result is saves being often corrupted.
im confused, do you happen to have any images of this done?
To have an image of this just look the traces on a board with a battery (or a slot for a battery) such as SNROM, SKROM, TKROM, etc...
I edited my original post so things are clearer how this is hooked up.