LM4560 datasheet(34/54 Pages) NSC

34 / 54 page

4.0 Functional Description (Continued)

4.1.3 Envelope engine

Low frequency AM, Envelope calculation and PAN are processed by Envelope Engine.

Terms:

Ec (12 bits) — Current envelope value in format of 6.6

AMS_H (2 bits) — Higher 2 bits of AMS

AMS_L (2 bits) — Lower 2 bits of AMS

AMS (4 bits) — Amplitude Modulation Step in format of 0.004 (right aligned with Ec)

SIN (4 bits) — current state of sin counter

AMA (8 bits) — Amplitude Modulation Amount in format of 2.6

VOL (8 bits) — Volume Attenuation per channel in format of 5.3

GVSEL (1 bit) — Global volume select bit

MUSICVOL_L (8 bits) — global music volume attenuation Left (6.2)

MUSICVOL_R (8 bits) — global music volume attenuation Right (6.2)

WAVEVOL_L (8 bits) — global wave volume attenuation Left (6.2)

WAVEVOL_R (8 bits) — global wave volume attenuation Right (6.2)

Eva (12 bits) — Current envelope after Volume attenuation

ATTNU_L (8 bits) — Left attenuation.

ATTNU_R (8 bits) — Right attenuation.

PAN (7 bits) — Positioning Attenuation (4.2 with one select bit)

EL (12 bits) — Left channel envelope value after PAN(6.6)

ER (12 bits) — Right channel envelope value after PAN(6.6)

VL (12 bits) — Left channel volume after anti-log operation

VR (12 bits) — Right channel volume after anti-log operation

EMOD (3 bits) — Envelope operation mode

ECNT (8 bits) — Envelope ramp counter

EINIT (8 bits) — Initial value of ECNT

EAMT (12 bits) — Envelope ramp amount

EDLY (20 bits) — Envelope delay counter

CEBF (1 bit) — Current Envelope Buffer Flag

4.1.4 Interpolation & Volume Adjusting

This multiply-add block process interpolation & volume adjusting.

Terms:

D1 (16 bits) — Current sample data (in MONO mode)

D1_L (16 bits) — Current sample data Left (in Stereo mode)

D1_R (16 bits) — Current sample data Right (in Stereo mode)

D2 (16 bits) — Sample data next to D1 (in MONO mode)

D2_L (16 bits) — Sample data next to D1_L (in Stereo mode)

D2_R (16 bits) — Sample data next to D1_R (in Stereo mode)

D (16 bits) — Data after interpolation (in MONO mode)

D_L (16 bits) — Data after interpolation Left (in Stereo mode)

D_R (16 bits) — Data after interpolation Right (in Stereo mode)

VL (12 bits) — Dry volume (Left)

VR (12 bits) — Dry volume (Right)

CVOL(7 bits) — Chorus Send Volume

RVOL(7 bits) — Reverb Send Volume

VDl (signed 20 bits) — volume adjusted Dry data (left)

VDr (signed 20 bits) — volume adjusted Dry data (right)

CSDl (signed 17 bits) — Chorus Send data (left)

CSDr (signed 17 bits) — Chorus Send data (right)

RSDl (signed 17 bits) — Reverb Send data (left)

RSDr (signed 17 bits) — Reverb Send data ( right )

1) Data conversion:

LM4560 数据表(PDF) 34 Page - National Semiconductor (TI)

LM4560 数据表(HTML) 34 Page - National Semiconductor (TI)

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