Retroactive 64drive, Руководство пользователя

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PAG E 7
D E V E L O P M E N T T O O L
U S E R ’ S M A N UA L
PAG E 8
Saving Methods
Games originally could contain custom
chips that held game progress inside the
physical cartridge. Appearing in decreas-
ing frequency in production carts:
• EEPROM (4Kbit)
• EEPROM (16Kbit)
• SRAM (256Kbit)
• FlashRAM (1Mbit)
• SRAM 3x (768Kbit)
Generally, first-party titles utilized these
kinds of built-in save mechanisms. As they
added cost to each unit built, cheaper
games relied on the user already owning a
Controller Pak (which is 256Kbit).
The last save type was used in only one
game, Dezaemon 3D. This Japan-only title
had three physical SRAM chips with some
glue logic to do rudimentary address
mapping.
The 64drive can emulate all of these
methods. A look-up table is used by the
menu to determine what kind of save
type should be assumed for each image
loaded. While this has been thoroughly
tested, it is still possible to override.
There are prototypes in the wild that
assume a certain save method and will
crash if it can’t be accessed. An example
is Mini Racers. In the worst case you can
try all 4 save types if a title hangs upon
boot.
As detailed before, save files can be
exchanged between emulators and the
64drive. All types except EEPROM files
must be 32bit endian swapped when
changing platforms.
Tech Details
This section pertains to information that
some may find useful as background
knowledge, or to further their understand-
ing with troubleshooting an odd issue.
Region Information
• NTSC - Used in the United States, Japan
• PAL - Used in most other countries such
as the UK, most of the EU, Australia
• MPAL - Brazil
For more detailed country listings consult
your favorite search engine.
To see what region console you have, flip
over your N64 and look at the printed
label on the bottom. The region is located
after the model number (NUS-001).
Cartridges original intended for sale in the
USA have notches on the rear lower cor-
ners of the cart case. Conversely, all other
parts of the world received cartridges
whose notches are inset by about 1cm.
It is possible for software running on the
N64 to detect what region of console it
is using. Some titles were able to adapt
to these changes and apply video and
sound changes to work in both regions.
Others were hard-coded to only accept
one region.
It is possible to have the 64drive to “fake”
the proper region, but since the actual
N64 hardware has different clocking
schemes, the video encoding (PAL vs
NTSC color encoding) and audio timing
will not be updated. The result is some
minor audio pops, and not all TVs will be
able to sync to the unconventional video
signal.
Once again a great deal about region
modding has been written. More informa-
tion on this subject can be found on the
Internet.
Of special note is the x105 CIC, which con-
tains additional functionality. It can accept
a “challenge” request and provide a magic
“response” value to the software running
on the N64, if so required.
Jet Force Gemini was the first title to
utilize this. In true Rareware style, the
game would still run on non-x105 CICs,
but it would crash randomly (on purpose)
and disallow the player from jumping or
shooting.
Banjo Tooie, another Rare title, took the
idea further. All the game assets were en-
crypted, and during runtime the respons-
es from the CIC challenges were used to
decrypt them. This was not defeated until
recently.
Lockout Chips
In addition to the physical notches in
each cartridge case, there was additional
region enforcement in original games.
Each cartridge contains a small microcon-
troller (CIC) that maintains constant
communication with a similar chip (PIF)
inside the N64 console. If the chip is
absent, the wrong type, or does not
exactly match the region, the system will
not boot.
The known CIC types for NTSC are:
• 6102
• 6101
• 6103
• 6105
• 6106
The known types for PAL are:
• 7101
• 7102
• 7103
• 7105
• 7106
Generally, the 6102/7101 is by far the
most common. Star Fox/Lylat Wars was
the first game to receive its own CIC, and
the trend continued with each major first-
party title.
In addition, the CIC inside the 64DD is
5101 which expects a NTSC-J console.