<18/29> SCSP User's Manual / 4.2.4 Volume

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SCSP User's Manual / 4.2 Sound Source Register

■ Volume register

TL [7: 0] (R / W); Total Level

The actual attenuation [dB] is the total value of the attenuation of the part where the bit is set to "1B" in the total level of 8 bits. Therefore, the larger the value set for "TL", the larger the attenuation and the lower the volume. Conversely, the smaller the value set for TL, the smaller the amount of attenuation and the louder the volume.

For example, the amount of attenuation when "FFH" is written is


--48 --24 --12 --6 --3 --1.5 --0.8 --0.4 = -95.7 [dB]

It will be.

Table 4.18 TL, attenuation and waveform amplitude

TL bit	bit 7	bit 6	bit 5	bit 4	bit 3	bit 2	bit 1	bit 0
TL attenuation	-48	-twenty four	-12	-6	-3	-1.5	-0.8	-0.4
Amplitude ratio	1/256	1/16	1/4	1/2	1 / √2	^1/4 √2	^1/8 √2	^1/16 √2
Real number ratio (times)	0.00391	0.06250	0.25000	0.50000	0.70711	0.84090	0.91700	0.95760

If only bit 4 is set to "1B", the amplitude of the output waveform after TL calculation becomes 1/2 of the amplitude in the waveform memory as shown in Fig. 4.50.

Figure 4.44 Wave data at TL bit4 = 1

SDIR (R / W); Sound DIRect

This flag is used to determine whether to output sound data directly. When this bit is "1B", the sound data is output without being multiplied by EG, TL, ALFO, etc.

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