Vin Terminal Usage Notes - Nintendo GAME BOY Programming Manual

3. VIN TERMINAL USAGE NOTES

• • • • The VIN terminal can be used normally only in CGB. (Since the signal from the VIN terminal is
too low to be used, the VIN terminal cannot be used in DMG.)
• • • • The maximum amplitude of the synthesized output is 3V.
• • • • The design prevents the maximum amplitude from exceeding 3V when only sounds 1-4 are
used, even when the output level for each sound is set to the maximum.
When the output level is set to 0Fh, each sound is output at 0.75V.
0.75V x 4 = 3V
• • • • The maximum amplitude of the synthesized sound output also must be limited to 3V or less
when the VIN terminal is used to input external sound.
Example: Using Sounds 1-4 and the VIN terminal
Use software to adjust the output levels of sounds 1-4 so that they do not exceed 0.6V
(3V ÷).Also limit the output level of the VIN terminal to 0.6V or less (input range of 1.9 - 2.5V).
• • • • The input voltage from the VIN terminal also can be increased if the levels of the internal
sounds are low or if not all 4 sounds are used (total output level of 3V or less).
+1.5V
+0.3
2.2V
+1.5V
-0.3
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Chapter 3: Sound Functions