MAX96706 Datasheet, PDF (71/73 Pages) Maxim Integrated Products – 14-Bit GMSL Deserializer with Coax or STP Cable Input

MAX96706
14-Bit GMSL Deserializer
with Coax or STP Cable Input
Table 11. Suggested Connectors and Cables for GMSL
VENDOR
CONNECTOR
CABLE
Rosenberger
59S2AX-400A5-Y
Dacar 302
Rosenberger
D4S10A-40ML5-Z
Dacar 538
Nissei
GT11L-2S
F-2WME AWG28
JAE
MX38-FF
A-BW-Lxxxxx
TYPE
Coax
STP
STP
STP
PRBS
The serializer includes a PRBS pattern generator that
works with bit-error verification in the deserializer. To
run the PRBS test, set PRBSEN = 1 (0x04, D5) in the
deserializer, then in the serializer. To exit the PRBS
test, set PRBSEN = 0 (0x04, D5) in the serializer. The
deserializer automatically ends PRBS checking and sets the
PRBS_OK bit high. Note that during PRBS mode, the
remote control channel is not available except to exit
PRBS mode if I2C_LOC_ACK=1; otherwise, the remote
control channel is not available at all.
To run the PRBS with a 3Gbps SerDes, or when HIBW
= 1, first set the PRBS_TYPE bit = 0 in the MAX967XX.
Then set PRBSEN = 1 (0x04, D5) in the serializer, then in
the deserializer. To exit the PRBS test, set PRBSEN = 0
(0x04, D5) in the deserializer, then in the serializer.
During PRBS test, ERRB function changes to reflect
PRBS errors only. ERRB goes low when any PRBS errors
occur. ERRB goes high when the PRBS error counter is
reset when PRBS_ERR is read. Normal ERRB function
resumes when exiting the PRBS test.
GPI/GPO
GPO on the serializer follows GPI transitions on the
deserializer. By default, the GPI-to-GPO delay is 0.35ms
(max). Keep the time between GPI transitions to a
minimum 0.35ms. GPI_IN the deserializer stores the GPI
input state. GPO is low after power-up. The µC can set
GPO by writing to the SET_GPO register bit. Do not send
a logic-low value on the deserializer RX/SDA input (UART
mode) longer than 100µs in either base or bypass mode
to ensure proper GPO/GPI functionality.
Fast Detection of Loss-of-Lock
A measure of link quality is the recovery time from loss
of synchronization. The host can be quickly notified of
loss-of-lock by connecting the deserializer’s LOCK output
to the GPI input (when PKTCC_EN = 0). If other sources
use the GPI input, such as a touch-screen controller, the
μC can implement a routine to distinguish between inter-
rupts from loss-of-sync and normal interrupts. Reverse
control-channel communication does not require an active
forward link to operate and accurately tracks the LOCK
status of the GMSL link. LOCK asserts for video link only
and not for the configuration link.
Providing a Frame Sync (Camera Applications)
The GPI and GPO provide a simple solution for camera
applications that require a frame sync signal from the
ECU (e.g., surround-view systems). Connect the ECU
frame sync signal to the GPI input and connect the GPO
output to the camera-frame sync input. GPI/GPO have a
typical delay of 275μs in legacy mode and 21μs in packet
mode (with 5-bit CRC). Skew between multiple GPI/GPO
channels is 115μs (max) in legacy mode and 21μs (max)
in packet mode. If a lower-skew signal is required in
legacy mode, connect the camera’s frame-sync input to
one of the serializer’s GPIOs and use an I²C broadcast
write command to change the GPIO output state. This has
a maximum skew of 1.5µs, independent from the used
I²C bit rate. In packet-based control-channel mode, set
GPI_COMP_EN = 1 in both the serializer and the dese-
rializer to turn on GPI/GPO compensation. This reduces
the device-to-device skew to 0.35μs.
Entering/Exiting Sleep Mode
The procedure for entering and exiting sleep mode
depends on the location of the microcontroller, and the
type of control-channel interface used. If wake-up from a
remote-side (serializer-side) microcontroller is not needed
or desired, set the DIS_RWAKE bit = 1 to shut down
remote wake-up for further power savings.
Legacy Control Channel
When μC is on the deserializer side, first put the serializer
to sleep, or disable serialization. Next, set SLEEP = 1 in
deserializer. The device sleeps after 8ms. To wake up the
device, send an arbitrary control-channel command to the
deserializer (the device will not send an acknowledge),
wait for 5ms for the chip to power up and then set SLEEP
= 0 to make the wake-up permanent.
When µC is on the serializer side, set SLEEP = 1 in dese-
rializer. Next, disable serialization. The device sleeps after
8ms. To wake up the deserializer, reenable serialization.
The deserializer wakes up and clears its SLEEP bit when
it locks to the serializer.
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