Rainbow Electronics MAX7470 User Manual
Page 14
MAX7469/MAX7470
HDTV Continuously Variable
Anti-Aliasing Filters
14
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VIDEO-SIGNAL FORMAT
F7
F6
F5
F4
F3
F2
F1
F0
CODE NO.
APPROXIMATE FREQUENCY
(-3dB) MHz
Standard Definition (Interlaced)
0
0
1
0
1
0
0
0
40
10
Standard Definition (Progressive)
0
1
0
1
1
0
1
0
90
15
High-Definition Low Bandwidth
1
1
0
1
1
1
0
0
220
30
High-Definition High Bandwidth
1
1
1
1
1
1
1
1
255
34 (default)
Table 6. Frequency Register Setting for Different Video-Signal Formats
selected in the command byte. Figure 8 shows a basic
read sequence.
Note: The master has to write a command byte,
requesting to read the control/status or frequency reg-
ister, to the slave (MAX7469/MAX7470) before the mas-
ter can read the contents of the selected register.
Control/Status Register
The MAX7469/MAX7470 store their status in an 8-bit
register that can be read back by the master. The indi-
vidual bits of the control/status register are summarized
in Tables 4 and 5. The power-on default value of this
register is 03h.
Frequency Register
The frequency response (-3dB passband edge) of the
MAX7469/MAX7470 can be continuously varied in 256
linear steps by changing the codes in the frequency reg-
ister (Table 6). See the
Command Byte
(
Write Cycle)
sec-
tion for a write sequence to update the frequency register.
SDA
SCL
1
0
0
1
0
A1
A0
R/W
C7
C6
C5
C4
C3
C2
C1
C0
ACK
ACK
OUT
IN
OUT
IN TO MAX7469/MAX7470
SDA (CONT)
SDA
DIRECTION
SDA
DIRECTION
SCL (CONT)
D7
D6
D5
D4
D3
D2
D1
D0
ACK
ACK
OUT
IN
IN
START
1
0
0
1
0
A1
A0
R/W
STOP
Sr
0
0
0
1
0
0
1/0
1
Figure 8. Basic Read Sequence
CONTROL/STATUS REGISTER
S7
S6
S5
S4
S3
S2
S1
S0
Table 4. Control/Status Register
Table 5. Control/Status Register Bit
Description
BIT
DESCRIPTION
S7
0 = component input signal selected (default).
1 = composite input signal selected.
S6
0 = internal sync enabled (default).
1 = external sync enabled.
S5
0 = external sync: positive polarity (default).
1 = external sync: negative polarity.
S4
0 = normal operation mode (default).
1 = power-down mode.
S3
0 = filters enabled (default).
1 = bypass mode—no filtering.
S2
0 = clamp voltage for IN1 set to low (default).
1 = clamp voltage for IN1 set to high.
S1
0 = clamp voltage for IN2 set to low.
1 = clamp voltage for IN2 set to high (default).
S0
0 = clamp voltage for IN3 set to low.
1 = clamp voltage for IN3 set to high (default).