TDA7522

16/23

– Constant Angular Velocity Control

– TOC management

– CD-Text I/F.

5.2 DSP (SACDSP : Servo Audio Control Digital Signal Processor)

DSP is placed as a subset of ST7 MPU, which performs Digital Filter calculation.

It consists of 20bit (data) x 16bit (coefficient) multiplier, 38bit accumulator, 20bit Data RAM, Data Arbitra-

tion between ST7, and 19 bits wide program Opcode; it can be broken down into two instruction bindings:

– Instruction binding #1

:Arithmetic Instructions + Parallel Move Instructions

– Instruction binding #2

:Immediate moves and bit-test jumps

SACDSP is very powerful DSP which performs more than 50MIPS, and it is based on three level pipeline

architecture in which concurrent instruction fetch, decode, and execution occur.

Figure 4. Basic I/Fs to ST7

Some Tasks of SACDSP are as follows;

– DSP: Digital Filter execution as slave of ST7

– Focusing and Tracking loop filter

– Sled Tracking control

– Pick-up Velocity control during Jump

Scratch RAM

ST7 & Peripherals

PROM

Data

Arbitration

Coeff.

Arbitration

Coeff.

RAM

Data

RAM

CIRC

Decimation

filter

SAC-DSP

PDM/PWM

Audio

DAC

PRAM

Loaded

AUDIO DATA Path

SERVO DATA Path

by ST7