Overview
The LC78624E is a CMOS LSI that implements the signal processing and servo control required by compact disc players. Including an EFM-PLL and text decoder, the LC78624E strictly limits functionality to basic signal processing and servo system operation to achieve the best cost-performance balance for low-end players. As basic functions, the LC78624E provides demodulation of the EFM signal from the optical pickup, de-interleaving, error detection and correction, and processes servo commands sent from the control microcontroller.

Features
• 64 pin QFP
• 5 V single-voltage power supply

Functions
• Input signal processing: The LC78624E 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.
• Precise reference clock and necessary internal timing generation using an external 16.9344 MHz crystal oscillator
• Disk 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 microcontroller
• Subcode Q signal output to a microcontroller over the serial I/O interface after performing a CRC error check (LSB first)
• Serial output to a microcontroller via the text decoder of the song titles and other text data stored in the Subcode R through W channels of the read-in area
• Demodulated EFM signal buffering in internal RAM to handle up to ±4 frames of disk 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 LC78624E 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 dual-interpolation scheme. The previous value is held if the C2 flags indicate errors two or more times consecutively.
• Support for command input from a microcontroller: commands include track jump, focus start, disk motor start/stop, muting on/off and track count (8 bit serial input)
• Built-in digital output circuits.
• Arbitrary track counting to support high-speed data access
• Zero cross muting
• Supports the implementation of a double-speed dubbing function.
• Support for bilingual applications.
• General-purpose I/O ports: 5 pins