December 02, 2022, 03:58:36 pm

Something that annoys you

Started by ericj, June 06, 2008, 05:22:35 pm

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Yup, at least according to Great Hierophant (who is a member here on the forum):
Quote from: Great HierophantHowever, there is a reason why you should wish to consider the X5 over the X7.  The X7 was developed before the X5.  The Genesis is a console that operates on 5v logic, but the Mega EverDrives use modern chips which operate with 3.3v logic levels.  When chips of different logic levels are interacting with each other, there should be level translator chips in the signal path to translate the logic levels accordingly.  If this is not done, then the higher voltages from the 5v parts and the lower voltages from the 3.3v parts will cause their counterparts to run out of specification.

When the v1 was designed, Krikzz mitigated the issue by using current limiting resistors on all the address and data lines.  The theory behind current limiting resistors is that instead of the clamping diodes inside the 3.3v chips dissipating the excess voltage from the 5v source as heat, the current limiting resistors do the job externally to the chips.  Heat is the enemy of silicon-based integrated chips.  If those diodes break down, then they could cause a short circuit and a voltage spike that could take the flash cart and even perhaps the console itself to the scrap heap.

Current limiting resistors limit the most obvious harmful effect, but the ICs are still being over/under volted whenever 1s are being output.  The X7 has 2 logic level translation chips, and these chips can handle 16 a piece.  Between the address and data lines, the cartridges have access to 40 signals alone, nevermind the additional signals used for other cartridge functions read enable, write enable and chip enable.  8 of the data lines and some other signals are still being serviced only by current limiting resistors.  When Krikzz designed the X5 and X3 at a later time, he added a third logic level shifter allowing for 48 signals, which is sufficient to handle all the signals the Mega EverDrive needs.
To summarize: the X7 does not fully protect the hardware (console and cartridge) from potentially taking damage as only 40 of 48 lines are protected. The X5 and X3 protects all 48 lines.

The Pro wasn't released yet when Great Hierophant wrote this review, but the Pro should also protect all 48 lines as I understood it.

Jedi Master Baiter

W00H00! ;D Bought one! ;D

Also, my package from Krikzz came in exactly as I ordered: a Super EverDrive X5 and an EverDrive GBA Mini as a gift for my brother for Christmas. :-X