HA12220 Hitachi Semiconductor, HA12220 Datasheet - Page 6

• Manufacturer Part Number: HA12220
• Description: CD-ROM Drive Head Amplifier IC
• Manufacturer: Hitachi Semiconductor

HA12220F
Operation
Control by Serial Data
The IC’s internal switches can be operated by sending control data from the HD49250.
The signal timing is shown in figure 1, and the control commands are listed in table 1 and 2.
Signals from the HD49250 are input at pins 14 to 16. Pin13 is connected to the microcomputer.
A low input at the XRST pin resets the IC. Normally this pin should be kept high.
The serial data from the HD49250 switches the following settings.
1. Tracking error EF balance
2. Focus offset
3. Tracking gain, Focus gain
4. FOK Vth
5. Mirror circuit, defect circuit normal speed / 4 speed / 8 speed mode
6. Tracking error cut-off frequency
7. APC amplifier ON/OFF
8. RF equalizer
9. Stand-by mode (cleared by setting XRST on)
Rev.1, Apr. 1997, page 6 of 20
Pin 15
Pin 14
Pin 16
DATA
CLK
XLT
Figure 1 Timing Diagram for Serial Data Control
Item
Clock frequency
Clock pulse width
Delay time
Latch pulse width
T1
0
T2
1
T1, T2
T3
T4
Symbol
f
CLK
2
3
Min
—
0.96
1
2
4
Typ
—
—
—
—
5
6
Max
520
—
—
—
T3
7
kHz
Unit
s
s
s
T4