An article examining many popular FLASH and multi game cartridges has just been brought to my attention, specifically looking at them from a point of safety.
I find it a little unnerving that even some of the well known FLASH carts seem to be doing things a little on the risky side. The cheap multi-carts, I’m not surprised about at all!
Relying on the chips’ clamping diodes to handle over voltage with only a current limiting resistor isn’t something I’d ever trust from a point of view of reliability, although you can actually see this exact thing shown in the datasheets of some CPLD’s. But it doesn’t sit well with me to do this. If the voltage is incompatible, you need to do some level shifting in one way or another.
And now to the point. The LynxSD is natively a 5v cartridge using SRAM and only communicating at 3.3v with the SD card through a resistor divider. So everything is good.
The NeoGeo Pocket SD is natively 3.3v (as is the NeoGeo Pocket), and uses 3.3v FLASH memory appropriately. So also all good!
The upcoming Jaguar SD is crammed full of level translators. In fact they account for the majority of the chips on the cartridge! Every connection to the Jaguars 5v bus is done via an appropriate level shifter.
Do things properly and you’ll only need to do them once!