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■ Volume register

TL[7:0](R/W) ; Total Level
In the total level of 8bit, the total attenuation of the part with the bit set to "1B" is the actual attenuation [dB]. Therefore, the greater the value set for "TL", the greater the attenuation and the lower the volume. Conversely, the smaller the value set for TL, the smaller the amount of attenuation and the greater the volume.
For example, the 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 bitbit 7bit 6bit 5bit 4bit 3bit 2bit 1bit 0
TL attenuation -48 -24 -12 -6-3-1.5-0.8-0.4
Amplitude ratio 1/256 1/16 1/4 1/21/√21/4√21/8√21/16√2
Real ratio (times) 0.00391 0.06250 0.25000 0.500000.707110.840900.917000.95760

Also, if only bit 4 is set to "1B", the amplitude of the output waveform after TL calculation will be 1/2 of the amplitude in the waveform memory as shown in Figure 4.50.

Figure 4.50 Wave data of TL bit4 [==] 1

SDIR(R/W) ; Sound DIRect
Flag for determining whether to output sound data directly. When this bit is "1B", sound data is output without being multiplied by EG, TL, ALFO, etc.

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