LC78681E Datasheet, PDF (12/23 Pages) Sanyo Semicon Device – Digital Signal Processor for Compact Disc Players

LC78681E
Notes: 1. When EFM signal noise results in errors in deceleration state determination, it may be advantageous to use
the internal brake control command (A3H) to change the EFM signal count from four to eight.
2. If focus is lost during execution of an internal brake command, it is necessary to first refocus and then input
the internal brake command again.
3. Due to the possibility of state determination errors due to the EFM signal playback state (e.g., damaged disk
or access in progress) we recommend that this product be used in conjunction with a microprocessor.
Track Jump Circuit
(pin 16: HFL, pin 17: TES, pin 20: TOFF, pin 21: TGL, pin 22: THLD, pin 25: JP ⁺ and pin 26: JP^–)
1. Internal Track Count
The following two modes are available.
MSB
LSB
00100010
00100011
Command
New track count (combination of TES and HFL)
Standard track count (direct count of the TES signal)
RES = low
The standard track count uses the TES signal without modification as the internal track count clock. In order to
reduce counting errors due to noise on the rising and falling edges of the TES signal, the new track counter
suppresses this noise through combination with the HFL signal, enabling an accurate track count. However, if the
HFL signal is lost because of foreign matter or scratching on the disk, no track count pulse may be generated. For
this reason, caution is required when using this mode.
No. 4521-12/23