CXD3018Q/R
§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 CXD2507AQ, and operation is the same as for the 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 output from the VCO to
the VCKI 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 $E6650 to set CAV-W mode and kick the disc,
then send $E60C0 to set CLV-W mode if ALOCK is high, which can be readout serially from the SQSO pin.
CLV 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 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
to high, deceleration pulses are not output, thereby achieving low power consumption mode.
Note) The capture range for CLV-W mode has theoretically the range 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 variable
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 $E6650 command and controlling
VP0 to VP7 with the $DX commands allows the rotational velocity to be varied from low speed to double
speed. (See the $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 for the velocity measurement
is a signal of 132.2kHz obtained by 1/128-frequency dividing the crystal (384Fs). The velocity is obtained by
counting V16M/2 pulses while the reference is high, and the result is output from the new CPU interface as
8 bits (VF0 to VP7). These measurement results are 31 when the disc is rotating at normal speed or 63 when it
is rotating at double speed. These values match those of the 256-n for control with VP0 to VP7.
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 all other
output signals 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.
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ETC [ ETC ]
