Hyundai H CDM8042 Car Stereo Circuit Diagram:

Used ICs:  SC9257 - SC6579 - S1L9226X

S1L9226X

As a pre-signal & servo signal processor for the DISC-MAN, S1L9226X is a low voltage, low consumption current IC that can read CD-RW, and CD-R discs and can be applied to various products, such as the CDP/VCD/CDMP3 for the DISC-MAN. It is a hard-wired free-adjustment servo, which automatically controlled the control point of the pre-signal portion.

FEATURES
RF Amplifier (CD, CD-R, CD-RW applicable)
Gain setting & monitoring for the CD-R, CD-RW DISC
RFAMP offset adjustment
Focus error amp & Febias adjustment
Tracking error amp & balance, gain adjustment
FOK, defect, mirror detect
Center voltage amplifier
APC (Automatic Power Control)
RF AGC & EQ control (AGC Level Control Compatible)
Enhanced EFM slice (Double Asymmetry Method)
Focus servo loop & offset adjustment
Tracking servo loop & offset adjustment
Sled servo loop
Spindle servo loop
Auto-sequence
Fast search mode (1 - 36000 track jump)
Interruption countermeasure
Focus & Tracking servo muting controlled by EFM duty check
RF peaking prevention system by EFM duty check
Focus, tracking, spindle loop pole move option
Operating voltage 2.7V ¾ 3.3V
Power saving mode
LPC Control used by side beam signal, it related to pick-up assurance.  When used pick-up, the specification is present extra.

SC9257 [PLL FOR DTS]

DESCRIPTION

The SC9257 is phase-locked loop (PLL) LSIs for digital tuning systems (DTS) with built in 2 modulus prescalers.

All functions ate controlled through 3 serial bus lines. These LSIs are used to configure high-performance digital tuning system.

FEATURES

> Optimal for configuring digital tuning systems in high-fi tuners and car stereos.

> built-in prescalers. Operate at input frequency ranging from 30~150 MHz during FMIN input (with 2 modulus prescaler) and at 0.5~40MHz during AMIN input (with 2 modulus prescaler or direct dividing).

> 16 bit programmable counter, dual parallel output phase comparator, crystal oscillator and reference counter.

> 3.6MHz, 4.5MHz, 7.2MHz or 10.8MHz crystal oscillators can be used.

> 15 possible reference frequencies. ( When using 4.5MHz crystal)

> Built-in 20 bit general-purpose counter for such uses as measuring intermediate frequencies (IFIN1 and IFIN2) and lowfrequency pilot signal cycles (SCIN).

> High-precision (±0.55~±7.15µs) PLL phase error detection.

> Numerous general-purpose I/O pins for such uses as peripheral circuit control.

> 4 N-channel open-drain output ports (OFF withstanding voltage:12V) for such uses as control signal output.
> Standby mode function (turns off FM, AM and IF amps) to save current consumption.
> All functions controlled through 3 serial bus lines.
> CMOS structure with operating power supply range of VDD=5.0±0.5V.

Schematic ( Circuit Diagram)

SC6579 [RADIO DATA SYSTEM (RDS) DEMODULATOR]
DESCRIPTION
The integrated CMOS circuit SC6579 is an RDS demodulator. It recovers the additional inaudible RDS information which is transmitted by FM radio broadcasting.  The data signal RDDA and the clock signal RDCL are provided as outputs for further processing by a suitable decoder (microcomputer).

FEATURES
Anti-aliasing filter (2nd order)
Integrated 57 kHz band-pass filter (8th order)
Reconstruction filter (2nd order)
Clocked comparator with automatic offset compensation
57 kHz carrier regeneration
Synchronous demodulator for 57 kHz modulated RDS signals
Selectable 4.332/8.664 MHz crystal oscillator with variable dividers
Clock regeneration with lock on bi-phase data rate
Bi-phase symbol decoder with integrate and dump functions
Differential decoder
Signal quality detector
Subcarrier output