LC78625E Schematic ( PDF Datasheet ) - Sanyo Semicon Device

Teilenummer	LC78625E
Beschreibung	Compact Disc Player DSP
Hersteller	Sanyo Semicon Device
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Gesamt 30 Seiten Ordering number : EN5502 CMOS LSI LC78625E Compact Disc Player DSP Overview The LC78625E is a CMOS LSI that implements the signal processing and servo control required by compact disc players, laser discs, CD-V, CD-I and related products. The LC78625E provides several types of signal processing, including demodulation of the optical pickup EFM signal, de-interleaving, error detection and correction, and digital filters that can help reduce the cost of CD player units. It also processes a rich set of servo system commands sent from the control microprocessor. It also incorporates an EFM-PLL circuit and a one-bit D/A converter. This LSI is an improved version of the LC78620E. In addition to supporting low-voltage operation, on/off control of the de-emphasis function and use of the bilingual function have been enabled in certain additional modes. Functions • The LC78625E takes an HF signal as input, digitizes (slices) that signal at a precise level, converts that signal to an EFM signal, and generates a PLL clock with an average frequency of 4.3218 MHz by comparing the phases of that signal and an internal VCO. • A precise reference clock and the necessary internal timings are generated using an external 16.9344 MHz crystal oscillator. • Disc motor speed control using a frame phase difference signal generated from the playback clock and the reference clock • Frame synchronization signal detection, protection, and interpolation to assure stable data readout • EFM signal demodulation and conversion to 8-bit symbol data • Subcode data separation from the EFM demodulated signal and output of that data to an external microprocessor • Subcode Q signal output (LSB first) to a microprocessor over the serial interface after performing a CRC error check • Demodulated EFM signal buffering in internal RAM to handle up to ±4 frames of disc rotational jitter • Demodulated EFM signal reordering in the prescribed order for data unscrambling and de-interleaving • Error detection, correction, and flag processing (error correction scheme: dual C1 plus dual C2 correction) • The LC78625E sets the C2 flags based on the C1 flags and a C2 check, and then performs signal interpolation or muting depending on the C2 flags. The interpolation circuit uses a quadruple interpolation scheme. The output value converges to the muting level when four or more consecutive C2 flags occur. Package Dimensions unit: mm 3174-QFP80E [LC78625E] SANYO: QFP80E SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN 22897HA (OT) No. 5502-1/35 LC78625E Figure 4 General-Purpose Port Input Timing Figure 5 General-Purpose Port Output Timing No. 5502-6/35 6 Page LC78625E • Command noise rejection Code $EF $EE COMMAND Command input noise reduction mode Reset the above mode. RES = L q This command reduces the noise on the CQCK clock signal. While this is effective for noise pulses shorter than 500 ns, the CQCK timings tWL, tWH, and tSU (see page 5, figures 1 and 2), must be set to be at least 1 µs. 6. Focus servo circuit; Pin 16: FOCS, pin 17: FST, pin 18: FZD, pin 70: LASER Code $08 $A2 $0A $8A $FE COMMAND FOCUS START #1 FOCUS START #2 LASER ON LASER OFF NOTHING RES = L q The FOCS, FST, and FZD pins are not required when the LC78625E is used in combination with an LA9230/40 Series LSI. FZD should be connected to 0 V when these pins are not used. The LA9230/40 Series focus start command is identical to the LC78625E FOCUS START #1 command. • NOTHING This command can be used to initialize the LC78625E by inputting FE (hexadecimal: Hexadecimal constants are written with a dollar sign ($) prefix). Note that $00 is the reset command for the LA9230/40 Series, and should be used with care since it clears the result of the automatic adjustment process and returns these chips to their initial states. • Laser control The LASER pin can be use as an extended output port. • Focus start When the LC78625E is used in combination with an LA9230/40 Series LSI, the focus start operation is executed completely on the servo side by commands from the control microprocessor. The following section describes this operation when the LC78625E is used in combination with an LA9210M or LA9211M. When a focus start instruction (either FOCUS START #1 or FOCUS START #2) is input as a servo command, first the charge on capacitor C1 is discharged by FST and the objective lens is lowered. Next, the capacitor is charged by FOCS, and the lens is slowly raised. FZD falls when the lens reaches the focus point. When this signal is received, FOCS is reset and the focus servo turns on. After sending the command, the microprocessor should check the in-focus detection signal (the LA9210 DRF signal) to confirm focus before proceeding to the next part of the program. If focus is not achieved by the time C1 is fully charged, the microprocessor should issue another focus command and iterate the focus servo operation. No. 5502-12/35 12 Page
Seiten	Gesamt 30 Seiten
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Teilenummer	Beschreibung	Hersteller
LC78625	Compact Disc Player DSP	Sanyo Semicon Device
LC78625E	Compact Disc Player DSP	Sanyo Semicon Device

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