?uniform? type. The regular PWM circuits output can be used (through an external RC filter
and servo amplifier device) to feed the spindle and sled motors of the loader.
The second task of the SERVO unit is to perform, under DSP control, fast and accurate jumps
to a given track of the disc or to the BCA position (for DVD discs) across the spiral track, or to
change layers for two layers DVD discs.
The third task of the SERVO unit is to identify the disc type.
10 VFD Controller
The VFD controller is a NEC uPD16311. This controller is not a processor, but does
include a simple state machine which scans the VFD and reads the front panel button
matrix. The
16311 also includes RAM so it can store the current state of all the VFD icons and
segments.
Therefore, the 16311 need only be accessed when the VFD status changes and when the
button
status is read. The V778 can control this chip directly using PIO pins or can allow the
front panel PIC to control the VFD.
11 Reset Circuitry
Sharp SV97 uses MAX809LTR SOT23 compatible RESET Ics.
Reset IC is connected to 5V line. In case of unstable power condition, reset IC resets the
software not to have an unwanted operation.
12 Connectors
12.1 Loader Connectors |
ACEC
SONY
