MAX9257AGCM+ Maxim Integrated, MAX9257AGCM+ Datasheet - Page 32

• Manufacturer Part Number: MAX9257AGCM+
• Description: Serializers & Deserializers - Serdes Prog Serializer / Deserializer
• Manufacturer: Maxim Integrated
• Type: Serializerr

Specifications of MAX9257AGCM+

• Rohs: yes
• Data Rate: 840 Mbit/s
• Input Type: LVCMOS
• Output Type: LVDS
• Number Of Inputs: 18
• Number Of Outputs: 1
• Operating Supply Voltage: 1.7 V to 3.6 V
• Operating Temperature Range: - 40 C to + 105 C
• Package / Case: LQFP-48
• Maximum Operating Temperature: + 105 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 1.71 V, 3 V

Figure 23. Control Channel Closing Due to ETO Timeout
After the MAX9257A detects the active VSYNC edge, it
sends three synchronization words. Once the MAX9258A
sees the active VSYNC transition and detects three syn-
chronization words, it enters the control channel phase
and CCEN goes high. There is a brief delay of T1 between
the VSYNC transition and CCEN transitioning high. The
ECU is allowed to communicate when CCEN is high.
If the ECU does not communicate while CCEN is high
(Figure
towards its preset timeout counter value. If STO times out
(T2), CCEN transitions low and the con trol channel closes.
If the ECU communicates while CCEN is high and before
STO expires
ETO timer is enabled. The ETO counter (ETOC NT+1) is
reset to 0 whenever activity from ECU (base mode) or
ECU and Camera (bypass mode) is detected. As long
as there is activity from ECU (base mode) or ECU and
Camera (bypass mode) on the link, the chan nel does not
close and the ETO counter resets. After the ECU (base
mode) or ECU and Camera (bypass mode) ceases link
activity, ETO times out (T4), CCEN transitions low, and
the control channel closes.
22), the link remains silent and STO starts counting
(Figure
VSYNC_IN
���������������������������������������������������������������� Maxim Integrated Products 32
DOUT_
T1 = TIME TO ENTER CONTROL CHANNEL
T4 = ETO TIMEOUT PERIOD
T5 = CONTROL CHANNEL EXIT TIME DUE TO ETO
HSK = HANDSHAKING BETWEEN MAX9257 AND MAX9258
SDI/O
CCEN
Fully Programmable Serializer/Deserializer
TX
RX
23), the STO timer is turned off and
Closing the Control Channel
VIDEO
T1
with UART/I
ACTIVITY
ECU
Another way to close the control channel in base mode
is for the ECU to send an end frame (EF) to close the
control channel without waiting for ETO to time out.
Whenever EF is received by both the devices, control
channel closes immediately and CCEN goes low. A syn-
chronization frame must precede EF. End frame cannot
be used in bypass mode. The control channel must close
by EF to report errors back to the ECU.
After the control channel closes, there is a brief hand shake
period (T3 in
MAX9257A and the MAX9258A. The MAX9258A sends a
special lock frame to the MAX9257A to indicate if PLL is
still locked. The MAX9258A sends the lock frame if the
number of decoding errors didn’t exceed a threshold in
the last LVDS video phase ses sion. The MAX9258A fea-
tures a proprietary VCO lock that prevents frequency drift
while in the control chan nel for extended periods of time.
If MAX9257A receives the lock frame, it understands that
the MAX9258A is in a locked state and sends a short
training sequence. If the lock frame is not received by the
MAX9257A, it assumes that the MAX9258A is not locked
and sends a long train ing sequence. After the short
or long training sequence is complete, the MAX9257A
FROZEN
T4 (BASE MODE)
MAX9257A/MAX9258A
T4 (BYPASS MODE)
2
Figure 22
C Control Channel
T5
HSK
and T5 in
VIDEO
Figure
23) between the