Author Topic: Technology behind the carts...  (Read 9632 times)

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Offline brainmegaphone

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Technology behind the carts...
« on: April 03, 2014, 05:26 AM »
I believe I read in posts that some of the ever drives are based in different technology than others...  Specifically I'm referring to the memory the game loads into.  Are some of the drives "writing" the games and then erasing them for each new game...  versus other drives which just load into memory?

I'm just curious in understanding the general idea behind the carts...  that's all...  I presume one tech is more expensive than others?

To this end - what is the GB cart based on?

Offline adimifus

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Re: Technology behind the carts...
« Reply #1 on: April 03, 2014, 07:13 AM »
It seems like its pretty similar to other flash carts (like the Smart Card 64M) except that you load the ROMs to the flash memory using the gameboy itself, rather than hooking it up to a PC to load a new game. That's why its more expensive, because it has additional circuitry to facilitate on-board flashing, the user interface, etc.
Everdrive N8 (Famicom), Everdrive N8 Pro (Famicom), SD2SNES rev E1, Game Doctor SF7, Everdrive 64 v2, Jaguar SD, PSIO
EMS USB 64M, Everdrive GB v1.1, Everdrive GB X7 rev B, Everdrive GBA X5, CycloDS Evolution + M3 GBA Expansion

Offline phoenixdownita

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Re: Technology behind the carts...
« Reply #2 on: April 03, 2014, 07:42 AM »
Actually some of the cards (Master Everdrive, Turbo Everdrive, EverdriveGG and others) use flash chips, so every game is flashed at load time (and it will survive a power reset), others instead use SRAM/RAM chips (Everdrive64, MegaED and EDN8 I believe).
Flash has only so many write cycles (in the 1000s or better) before it breaks, but SRAM/RAM does not have the issue, but it looses its content on power down. Everdrive64 reloads the game if you press the button as it stores on the SD what was the last game loaded, not sure if MegaED and EDN8 use the same trick.

Also the flash based devices use FeRAM for games that have save support (none for TurboED which then has no FeRAM at all), not sure what ED64/MegaED/EDN8 use if anything but just SRAM with battery back up.

For the rest the big part is done by a CPLD (for simpler devices like MasterED, TurboED) or CPLD + FPGA (ED64, MegaED and others). Those chips are responsible to implement mapping the RAM/flash into addressable space where applicable and switch it as the game expects it, FPGAs come into play to simulate mapper chips special/advanced  features where applicable (like EDN8).

Krikzz uses Altera chips for CPLD (MaxII) and FPGA (CycloneII), but there are other alternatives, I believe SD2SNES uses Xilinx.
« Last Edit: April 03, 2014, 07:50 AM by phoenixdownita »

Offline adimifus

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Re: Technology behind the carts...
« Reply #3 on: April 03, 2014, 08:07 AM »
Ah, I misread his post. I thought he was asking about other gameboy flash carts vs the Everdrive GB.

The N8 does have the "load last ROM" feature, like the ED64.
Everdrive N8 (Famicom), Everdrive N8 Pro (Famicom), SD2SNES rev E1, Game Doctor SF7, Everdrive 64 v2, Jaguar SD, PSIO
EMS USB 64M, Everdrive GB v1.1, Everdrive GB X7 rev B, Everdrive GBA X5, CycloDS Evolution + M3 GBA Expansion

Offline brainmegaphone

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Re: Technology behind the carts...
« Reply #4 on: April 03, 2014, 09:05 PM »
Very helpful thanks!  So it would seem some of the devices have a life cycle due to flash (although I can't imagine how many years that would be considering you get in the 1000s for re writes)...

Offline tokumaru

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Re: Technology behind the carts...
« Reply #5 on: April 04, 2014, 06:24 PM »
I'm not sure what kind of Flash memory is used in Krikzz's carts, but I believe it's not uncommon to find Flash memory that supports up to 100.000 write cycles. That would allow you to flash 4 games every day for 68 years. More than adequate, I'd say. I still prefer the RAM-based carts though... my OCD side enjoys loading multiple new games every play session.

Offline nuu

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Re: Technology behind the carts...
« Reply #6 on: April 04, 2014, 09:11 PM »
By 68 years, other components are bound to need replacement, so the life of a flash memory isn't that different from the life of many other parts I believe.

Offline tokumaru

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Re: Technology behind the carts...
« Reply #7 on: April 05, 2014, 02:16 AM »
In 68 years I'm sure I'll be dead, so I'm fine! ;D

Offline KRIKzz

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Re: Technology behind the carts...
« Reply #8 on: April 05, 2014, 10:47 AM »
The N8 does have the "load last ROM" feature, like the ED64.
Actually N8 have "load last ROM" feature also

Offline brainmegaphone

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Re: Technology behind the carts...
« Reply #9 on: April 15, 2014, 07:08 AM »
So to be clear - half of the EDs write to flash memory and the other half write (or load) to a form of RAM?

Offline mrpopsicleman

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Re: Technology behind the carts...
« Reply #10 on: April 15, 2014, 07:42 AM »
So to be clear - half of the EDs write to flash memory and the other half write (or load) to a form of RAM?
Yes, that is correct.

Offline brainmegaphone

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Re: Technology behind the carts...
« Reply #11 on: April 15, 2014, 04:39 PM »
How does Krikzz decide which technology to use?  Size of roms?  Or is cost the main factor?

Offline adimifus

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Re: Technology behind the carts...
« Reply #12 on: April 16, 2014, 11:46 PM »
How does Krikzz decide which technology to use?  Size of roms?  Or is cost the main factor?

Maybe power draw? RAM needs continuous power to keep its contents, but flash doesn't. As far as I know, flash is cheaper than RAM so that would be a factor, too. RAM is nicer because there is no limitation to how many times you can write to it, and if you play different games a lot, its much quicker writing to it.

Actually, I think most of his carts use flash

Flash Carts - Everdrive [MD], Super Everdrive, Master Everdrive, Everdrive GG, Everdrive GB, Turbo Everdrive
RAM Carts - Everdrive 64, Mega Everdrive, Everdrive N8

right?
« Last Edit: April 16, 2014, 11:49 PM by adimifus »
Everdrive N8 (Famicom), Everdrive N8 Pro (Famicom), SD2SNES rev E1, Game Doctor SF7, Everdrive 64 v2, Jaguar SD, PSIO
EMS USB 64M, Everdrive GB v1.1, Everdrive GB X7 rev B, Everdrive GBA X5, CycloDS Evolution + M3 GBA Expansion