I'm a beginner in the electronics world. I opened this Chinese bootleg Sega genesis cartridge and in the place I expected to find a tsop flash chip I found this kind of adapter board with a package without label I can't recognize. It seems the board has only a transistor so it might be just a pin-by-pin adapter? I wonder why it has so many soldering points and space for other components. How would I go about guessing what kind of chip it is?
That's just a similar flash memory chip in BGA package, mounted on an adapter to make it fit in place of the original TSOP package flash.
There is no transistor on the board.
What there looks like to be is just a 0 ohm link resistor.
The empty places are for components that may be required but maybe not with this memory chip.
They can be places for other 0R resistors used to route the signals differently to the memory chip, to allow for different types or sizes of BGA memory chips.
So it might be a pin-by-pin adapter but just a configurable one.
They may also be places for capacitors if the flash chip needs further bypassing, if wiring to the main board capacitors is too long and mainboard capacitors are not enough for bypassing.
If you are going to make an adapter, you might as well make one that is flexible enough for all kinds of different flash chips, instead of making just one for a specific chip, and make another for a different chip.
It's also possible that the configuration options select a part of memory space to show to the CPU, so you can manufacture many different types of gaming consoles and the flash chips contain all the games, but only the specific set of games in memory is shown to the CPU.
We can only guess, the list is endless. One component seems to be for a diode. Cannot guess what it might do. Could be a power indicator LED.
The same adapter could be used for a lot of different consoles too, not just this one, so that's why the options that determine either the used memory chip or the console this is mounted on.
