AGB FAQ, Mobile

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## Backup

[Q001] What cautions should I take regarding backup?
[Q002] Is there a way to detect whether or not backups are being performed?
[Q003] Is it possible to develop a backup memory part for the Probe Cartridge 1 or 2?
[Q004] Tell me about the backup memory's write cycle lifetime.
[Q005] What happens when the Game Pak is removed while the backup memory is accessed?

### [Q001]

What cautions should I take regarding backup?

### [A001]

Dealing with Damaged Back-up Data (Required)

Ensure that the program continues to function as intended even if the power switch is turned off while data is being saved. (The data must be restored or the memory must be re-initialized.)

Discussion

It is impossible to prevent the destruction of data when the power is turned off while data is being saved.

Remarks

Examples of measures to take for back-up data which has been destroyed are:

Error Detection -------- Check-sum / CRC

Detection of abnormal data by the game program.

Use a flag which indicates completion of the data saving process.

For example:

When initializing the saved data, an initialization finish flag (or dirty bit) should not be written until after initialization is completed. Push the Reset Switch during the initialization process to make sure that no abnormalities occur during subsequent initialization attempts.

Backup Memory Initialization (Required)

Ensure that the initialization process works properly even when the content of the back-up memory is undefined.

Discussion

A specific value is stored in the back-up memory when it is shipped from the factory. However, the value that is stored may change in the future without notification. Therefore, your initialization process must include initialization of back-up memory no matter what value it may contain.

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### [Q002]

Is there a way to detect whether or not backups are being performed?

### [A002]

No. Please use another method such as writing a check flag.

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### [Q003]

Is it possible to develop a backup memory part for the Probe Cartridge 1 or 2?

### [A003]

By combining the IS-AGB-DEBUGGER + Probe Cartridge 1 or 2, it is possible to access backup memory, but we cannot guarantee its operation. See details below:

- If the IS-AGB-DEBUGGER has not yet been converted to the I version, the backup memory cannot be accessed via the IS-AGB-DEBUGGER.
- If the IS-AGB-DEBUGGER has already been converted to the I version, the backup memory can be accessed via the IS-AGB-DEBUGGER.

However, the operation is not guaranteed, so a message warning the user about this is displayed. Users who want to proceed can go ahead and debug programs that access backup RAM. (Specifically, this is done by inserting the AGB Flash Pak + backup RAM into the slots on the IS-AGB-DEBUGGER and setting the Memory Settings option to "Use internal memory for ROM and external memory for RAM.")

-If you have the DMG CARTRIDGE PROBE 3(C), backup memory is directly connected so access to backup memory is guaranteed and debugging can be performed.

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### [Q004]

Tell me about the write cycle lifetime in the backup memory.

### [A004]

Here is a general idea:
- 4Kbit EEPROM --->> 100,000 times
- 512K Flash --->> 10,000 times in a sector (no limit on the number of reads)
- 256KSRAM --->> No limit as long as long as the battery retains a charge.

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### [Q005]

What happens when the Game Pak is removed while the backup memory is accessed?

### [A005]

There is a possibility that data will be destroyed when the Game Pak is removed while memory is being accessed. This is true for all the backup devices. Also, please note that there is a chance of data being destroyed even in a sector that is not being accessed if the CPU crashes.

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D.C.N. AGB-06-0027-001A1 (2/21/01)
© 2001 Nintendo of America Inc.