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Detailed Description
The MAX9277/MAX9281 serializers, when paired with
the MAX9276/MAX9280 deserializers, provides the full
set of operating features, but is backward compatible with
the MAX9249–MAX9270 family of Gigabit Multimedia
Serial Link (GMSL) devices, and have basic functionality
when paired with any GMSL device. The MAX9281 has
High-bandwidth Digital Content Protection (HDCP) while
the MAX9277 does not.
The serializer has a maximum serial-bit rate of 3.12Gbps
for up to 15m of cable and operates up to a maximum
output clock of 104MHz in 24-bit, 3-channel mode and
27-bit high-bandwidth mode, or 78MHz in 32-bit, 4-chan
-
nel mode. This bit rate and output flexibility support a wide
range of displays, from QVGA (320 x 240) to 1920 x 720
and higher with 24-bit color, as well as megapixel image
sensors. An encoded audio channel supports L-PCM I
2
S
stereo and up to eight channels of L-PCM in TDM mode.
Sample rates of 32kHz to 192kHz are supported with
sample depth from 8 to 32 bits. Output pre/deemphasis,
combined with GMSL deserializer equalization, extends
the cable length and enhances link reliability.
The control channel enables a µC to program the serial
-
izer and deserializer registers and program registers on
peripherals. The control channel is also used to perform
HDCP functions (MAX9281 only). The µC can be located
at either end of the link, or when using two µCs, at both
ends. Two modes of control-channel operation are availa
-
ble. Base mode uses either I
2
C or GMSL UART protocol,
while bypass mode uses a user-defined UART protocol.
UART protocol allows full-duplex communication, while
I
2
C allows half-duplex communication.
Spread spectrum is available to reduce EMI on the serial
output. The serial output and LVDS input complies with
ISO 10605 and IEC 61000-4-2 ESD protection standards.
Register Mapping
Registers set the operating conditions of the serializers
and are programmed using the control channel in base
mode. The MAX9277/MAX9281 holds its own device
address and the device address of the deserializer with
which it is paired. Similarly, the deserializer holds its
own device address and the address of the MAX9277/
MAX9281. Whenever a device address is changed be
sure to write the new address to both devices. The default
device address of the serializer is set by the ADD[1:0]
(see
Table 1
). Registers 0x00 and 0x01 in both devices
hold the device addresses.
Table 1. Device Address Defaults (Register 0x00, 0x01)
*
X = 0 for the serializer address, X = 1 for the deserializer address.
PIN
DEVICE ADDRESS
(bin)
SERIALIZER
DEVICE
ADDRESS
(hex)
DESERIALIZER
DEVICE
ADDRESS
(hex)
ADD1
ADD0
D7
D6
D5
D4
D3
D2
D1
D0
Low
Low
1
0
0
X*
0
0
0
R/
W
80
90
Low
High
1
0
0
X*
0
1
0
R/
W
84
94
Low
Open
1
0
0
X*
1
0
0
R/
W
88
98
High
Low
1
1
0
X*
0
0
0
R/
W
C0
D0
High
High
1
1
0
X*
0
1
0
R/
W
C4
D4
High
Open
1
1
0
X*
1
0
0
R/
W
C8
D8
Open
Low
0
1
0
X*
0
0
0
R/
W
40
50
Open
High
0
1
0
X*
0
1
0
R/
W
44
54
Open
Open
0
1
0
X*
1
0
0
R/
W
48
58
MAX9277/MAX9281
3.12Gbps GMSL Serializers for Coax or
STP Output Drive and LVDS Input
www.maximintegrated.com
Maxim Integrated │
26