CXD3018Q/R
§5-8. TRK (Tracking) and SLD (Sled) Servo Control
The TRK and SLD servos are controlled by the 8-bit command $2X. (See Table 5-9.)
When the upper 4 bits of the serial data are 2 (h), TZC is output to the SENS pin.
Command
D19 to D16
0 0
Register name
D23 to D20
TRACKING SERVO OFF
TRACKING SERVO ON
FORWARD TRACK JUMP
REVERSE TRACK JUMP
SLED SERVO OFF
0 1
1 0
1 1
TRACKING
MODE
2
0 0 1 0
0 0
SLED SERVO ON
0 1
FORWARD SLED MOVE
REVERSE SLED MOVE
1 0
1 1
: don't care
Table 5-9
TRK Servo
The TRK JUMP (track jump) level can be set with 6 bits (D13 to D8) of $36.
In addition, when the TRK servo is on and D17 of $1 is set to 1, the TRK servo filter switches to gain-up mode.
The filter also switches to gain-up mode when the LOCK signal goes low or when vibration is detected with the
anti-shock circuit (described hereafter) enabled.
The CXD3018Q/R has 2 types of gain-up filter structures in TRK gain-up mode which can be selected by
setting D16 of $1. (See Table 5-17.)
SLD Servo
The SLD MOV (sled move) output, composed of a basic value from 6 bits (D13 to D8) of $37, is determined by
multiplying this value by 1×, 2×, 3×, or 4× set using D17 and D16 when D18 = D19 = 0 is set with $3. (See
Table 5-10.)
SLD MOV must be performed continuously for 50µs or more. In addition, if the LOCK input signal goes low
when the SLD servo is on, the SLD servo turns off.
Note) When the LOCK signal is low, the TRK servo switches to gain-up mode and the SLD servo is turned off.
These operations are disabled by setting D6 (LKSW) of $38 to 1.
Command
SELECT
D19 to D16
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
Register name
3
D23 to D20
0 0 1 1
SLED KICK LEVEL (basic value × ±1)
SLED KICK LEVEL (basic value × ±2)
SLED KICK LEVEL (basic value × ±3)
SLED KICK LEVEL (basic value × ±4)
Table 5-10
– 94 –
ETC [ ETC ]
