LC78622NE Datasheet, PDF (30/31 Pages) Sanyo Semicon Device – Compact Disc Player DSP

LC78622NE
Continued from preceding page.
• EFM signal lines should be kept as short as possible, and either adjacent lines should be avoided or V_DD or ground
shield lines should be run between adjacent EFM signal lines.
Since the slice level controller output (EFMO) and the ASP clock output (4.2MHz) lines can easily disrupt EFM signal
lines, resistors connected to output pins should be located extremely close to the pin. Note that the smaller these
resistors, the larger the amount of spurious radiation emitted. Inversely, the output level may be adversely influenced if
the resistors are made too large. Design the 4.2MHz output according to the ASP input level requirements. (Design
center: 1 V p-p)
• Noise on the microcontroller interface signal lines can result in incorrect operation. While the best method for reducing
noise depends on the application itself, in general, the interface lines should be made as short as possible and
inductances and capacitances minimized. However, designs must also take crosstalk into account.
If long interface lines must be used, or if noise is a problem, inserting a noise exclusion circuit may be effective.
Design noise filters with the interface timing taken into account. Issuing the command noise reduction command [$EF]
may also be effective.
• Cover the area around the crystal oscillator element with the ground pattern.
Notes on Software Design
• Always follow the recommendations for software design provided in the IC documentation and do not use any
techniques specifically forbidden.
• If the digital outputs are used, issue a UBIT OFF [$41] command to this IC during initialization. UBIT ON [$40]
should only be used during playback to prevent DIR unlock and incorrect subcode recognition.
• During initialization, after clearing an IC reset, and after turning this IC's oscillator on, issue a 2-byte reset command
[$FF] to the LA9230M Series or LA9240M Series ASP to set up the ASP command register.
• Since the LA9230M Series and LA9240M Series ASP ICs use the 4.2MHz output from this IC as their master clock, an
additional 30 ms of setup time is required after the oscillator stabilization time during initialization, after clearing an IC
reset, and after turning this IC's oscillator on. This 30 ms of setup time is also required after issuing an ASP reset
command [$00] to the ASP.
• Since the command timing for the LA9230M Series and LA9240M Series ASP ICs is slower than that for this IC, be
sure to refer to the ASP IC documentation when designing application software.
Other Notes
If you have any questions, please do not hesitate to contact your Sanyo representative, or your Sanyo semiconductor sales
outlet.
Since this IC is specifically designed for use in CD players, its specifications differ from those of standard logic and other
general-purpose IC products. We recommend adopting failsafe design techniques in the applications, and we also
recommend debugging applications in the application equipment itself.
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