SM9403BM Datasheet, PDF (11/18 Pages) Nippon Precision Circuits Inc – DVDRAM Servo-amplifier LSI

SM9403BM
FUNCTIONAL DESCRIPTION
Serial Interface
The SM9403BM uses a serial interface comprising 5
ports to control and set all functions. The address and
bit configuration of each port is shown in table 1
Table 1. Port address and bit configuration¹
Bit number
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Data
Address
MSB
LSB
DPE HAE FFE TFE SWB SWA SL2 SL1 × LOW LOW LOW HIGH LOW ×
×
OF3 OF2 OF1 WD2 WD1 HS3 HS2 HS1 × LOW LOW LOW HIGH HIGH ×
×
THE FHE HRE MM2 MM1 LS3 LS2 LS1 × LOW LOW HIGH LOW LOW ×
×
EQE CG3 CG2 CG1 DL4 DL3 DL2 DL1 × LOW LOW HIGH LOW HIGH ×
×
TS3 TS2 TS1 –
–
– DG2 DG1 × LOW LOW HIGH HIGH LOW ×
×
1. × = don’t care, – = unassigned
Serial data is input on SDATA with the LSB first, in
sync with the falling edge of the SCLK clock. After
the 16th SCLK falling edge and 16 bits of valid data
has been input, the SDATA n-channel open-drain
output goes LOW as an acknowledge signal.
If the number of SCLK cycles which occur when
SENB (serial interface enable) is HIGH is less than
16, the received data is ignored and the internal port
is not updated. If the number of SCLK cycles is
greater than 16, the data is still considered value up
to the 16th SCLK falling edge, the data is latched
into the internal port, and the acknowledge signal is
output. The acknowledge signal is held until SENB
goes LOW again.
Focus Sample-and-Hold/Low-pass Filter (FSUB → FER)
This stage, the signal which is generated from the
header position detector signal samples and holds the
focus error signal. The output then passes through a
low-pass filter. This low-pass filter can be turned ON
or OFF using the serial interface control bit FFE.
Table 2. Focus low-pass filter ON/OFF control
FFE
Low-pass filter¹
LOW
ON
HIGH
OFF
1. Default is ON
Tracking Sample-and-Hold/Low-pass Filter (TSUB → TRE)
This stage, the signal which is generated from the
header position detector signal samples and holds the
tracking error signal. The output then passes through
a low-pass filter. This low-pass filter cutoff frequency
can be switched using the serial interface control bit
TFE.
Table 3. Tracking low-pass filter cutoff frequency
TFE
Low-pass filter¹
LOW
HIGH
1. Default is 160kHz
f_C = 160kHz
f_C = 35kHz
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