Nintendo GAME BOY Programming Manual page 232

Game Boy Programming Manual
5.6.3 Specifying External Sound Input (VIN)
Always use the sound control register (NR50) with bits 7 and 3 set to 0 (VIN function OFF).
Because the VIN terminal is used in development flash ROM cartridges, using the register with
VIN set to ON will produce sound abnormalities.
5.6.4 Disabling Vibration Using the SGB, SGB2, or 64GB Pak
When MBC5 is used by SGB, SGB2, or the 64GB Pak, vibration should be turned off by the
program to prevent failures caused by a faulty connection. For methods of recognizing SGB
and SGB2, see the description of the MLT_REQ command in Chapter 6, Section 3.2, System
Command Details. With the 64GB Pak, vibration is controlled by the N64 software. Therefore,
N64 software programs that support MBC5 should not write data to bit 3 of the RAM bank
register.
5.6.5 Limiting the Period of Continuous Vibration
To prevent physical effects in the user such as numbness as a result of continuous vibration,
limit the duration of continuous vibration as indicated below, regardless of the vibration strength
(see Section 6.5.2, Vibration Pulse Examples).
! The duration of continuous vibration should generally be limited to a maximum of 1 minute.
! The period of no vibration between the finish of one period of vibration and the start of the
next period generally must be at least as long as the vibration time.
The above points are guidelines that should be followed in most cases. However, if adhering to
these guidelines is made difficult by factors such as the game content, take appropriate
measures while keeping in mind the points noted in Section 6.7, Effects of Vibration on the
Body.
5.6.6 Disabling Vibration for Resets and Pauses
Vibration should be halted during resets and pauses.
When power is turned on, the unit should not be vibrated until some input is received from the
controller.
5.6.7 Rumble Feature Selection
The user should be allowed to set the rumble feature to ON or OFF or to select strong, mild, or
OFF by means such as an initial-settings screen at the start of the game. In addition, the
program should allow the user to easily change these settings even during a game if, for
example, they are uncomfortable with the vibration. Such changes also should be allowed a
pause.
5.6.8 Changes in Vibration Level with Battery Use
If the battery that powers the motor (Size AAA alkaline battery) wears out, the perceived
vibration level will be reduced even if the requested vibration level remains the same.
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