BBK PV420S, Руководство по обслуживанию

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CXD3068Q
[3] Description of Modes
This LSI has three basic operating modes using a combination of spindle control and the PLL. The operations
for each mode are described below.
§ 3-1. CLV-N Mode
This mode is compatible with the CXD2510Q, and operation is the same as for conventional control. The PLL
capture range is ±150kHz.
§ 3-2. CLV-W Mode
This is the wide capture range mode. This mode allows the PLL to follow the rotational velocity of the disc. This
rotational following control has two types: using the built-in VCO2 or providing an external VCO. The spindle is
the same CLV servo as for the conventional series. Operation using the built-in VCO2 is described below.
(When using an external VCO, input the signal from the VPCO pin to the low-pass filter, use the output from
the low-pass filter as the control voltage for the external VCO, and input the oscillation from the VCO to the
V16M pin.)
When starting to rotate the disc and/or speeding up to the lock range from the condition where the disc is
stopped, CAV-W mode should be used. Specifically, first send $E665X to set CAV-W mode and kick the disc,
then send $E60CX to set CLV-W mode if ALOCK is high, which can be read out serially from the SQSO pin.
CLV-W mode can be used while ALOCK is high. The microcomputer monitors the serial data output, and must
return the operation to the speed adjusting state (CAV-W mode) when ALOCK becomes low. The control flow
according to the microcomputer software in CLV-W mode is shown in Fig. 3-2.
In CLV-W mode (normal), low power consumption is achieved by setting LPWR to high. Control was formerly
performed by applying acceleration and deceleration pulses to the spindle motor. However, when LPWR is set
high, deceleration pulses are not output, thereby achieving low power consumption mode.
Note) The capture range for this mode is theoretically up to the signal processing limit.
§ 3-3. CAV-W Mode
This is CAV mode. In this mode, the external clock is fixed and it is possible to control the spindle to the
desired rotational velocity. The rotational velocity is determined by the VP0 to VP7 setting values or the
external PWM. When controlling the spindle with VP0 to VP7, setting CAV-W mode with the $E665X command
and controlling VP0 to VP7 with the $DX commands allows the rotational velocity to be varied from low speed
to 4
×
speed. (See "$DX commands".) Also, when controlling the spindle with the external PWM, the PWMI pin
is binary input which becomes KICK during high intervals and BRAKE during low intervals.
The microcomputer can know the rotational velocity using V16M. The reference frequency for the velocity
measurement is a signal of 132.3kHz obtained by dividing XTAL (XTAI, XTAO) (384Fs) by 128. The velocity is
obtained by counting the half of V16M pulses while the reference is high, and the result is output from the new
CPU interface as 10 bits (VP0 to VP9). These measurement results are 31 when the disc is rotating at normal
speed or 127 when it is rotating at 4
×
speed. These values match those of the 256 - n for control with VP0 to
VP7. (See Table 2-5 and Fig. 2-6.)
In CAV-W mode, the spindle is set to the desired rotational velocity and the operation speed for the entire
system follows this rotational velocity. Therefore, the cycles for the Fs system clock, PCM data and others
output from this LSI change according to the rotational velocity of the disc.
Note) The capture range for this mode is theoretically up to the signal processing limit.
Note) Set FLFC to 1 for this mode