CXD3021R Datasheet, PDF (79/161 Pages) Sony Corporation – CD Digital Signal Processor with Built-in Digital Servo and DAC

CXD3021R
[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 (however,
variable pitch cannot be used). 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 $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.
CLV-W mode supports control only by the ternary output of the MDP pin. Therefore, when using CLV-W mode,
set DCLV PWM MD to low.
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 $DX commands allows the rotational velocity to be varied from low speed
to 32× speed. (See "$DX commands".) When controlling the spindle with the external PWM, CAV-W mode is
set with the $E6A5X command. Then, 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 132.3kHz obtained by 1/128-frequency dividing the crystal (XTLI, XTLO) (384Fs). 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 (VF0 to 9). These measurement results are 31 when the disc is rotating at normal
speed or 127 when it is rotating at quadruple 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 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.
Note) Set FLFC to 1 for this mode.
– 79 –