I checked this out with our engineer. You can install a simple 3V CR2032 battery on Carnivore2's board. Or you can install a 3.3v Gold-Cap, but in this case, you need to bridge the D2 diode that protects the battery. Also the resistor that stands between the Gold-Cap and the power bus should be reduced to 100 Ohm. Otherwise the Gold-Cap won't work properly.
Oh, I had always thought that this functionality was included out of the box, which apparently means a battery must be installed.
For reference, the manual:
引用:
The FMPAC's 8kb SRAM is emulated by the cartridge at the Shadow RAM's address 0FE000h. This area is not affected by the 1mb of primary RAM in any way. This area is used by certain games to save the data. If the Carnivore2 cartridge doesn't have a backup RAM battery installed, then the data that was saved into that area will be lost when an MSX computer is switched off. As this data survives the reset, it's possible to save it to a file and load it back into RAM when needed. The utility that allows to save/load this data is called C2SRAM.COM. The files with the save data will have .SRM extension by default and these files will be found by the utility when a user selects files manually. However the file can be saved with any name and extension. In such a case when a user wants to upload the file into the emulated SRAM area, he will have to type its name manually.
To save the data it's enough to reset MSX (no power–off!), run the “C2SRAM.COM” utility and save the data to a file. Then a computer can be switched off. In case a user wants to restore the data and then run a game, the C2SRAM.COM utility should be used to upload the previously saved file into SRAM area. Then a computer should be reset and a game can be then started from the Boot Menu or from an emulated DSK image.
Installing a battery or a goldcap was never planned. There's no space in the case for a battery holder. So the battery needs to be with wires, like in the old IBM laptops. Finding such battery is a problem, besides, it will raise the price of the cartridge. As most of games don't use SRAM, the battery was never considered the must-have option. The C2SRAM utility can save/load data into Carnivore2, so this is a good workaround.
