TDA7522 Datasheet, PDF (16/23 Pages) STMicroelectronics – Digital Servo & Decoder

TDA7522
– 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
Scratch RAM
ST7 & Peripherals
PROM
Coeff.
RAM
Coeff.
Arbitration
Data
Arbitration
Data
RAM
Decimation
filter
PRAM
Loaded
by ST7
SAC-DSP
PDM/PWM
SERVO DATA Path
CIRC
AUDIO DATA Path
Audio
DAC
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
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