MAX9257GTL/V+ Maxim Integrated Products, MAX9257GTL/V+ Datasheet - Page 28

• Manufacturer Part Number: MAX9257GTL/V+
• Description: IC SER/DESER PROG 40TQFN-EP
• Manufacturer: Maxim Integrated Products

Specifications of MAX9257GTL/V+

• Function: Serializer/Deserializer
• Data Rate: 840Mbps
• Input Type: Serial
• Output Type: LVDS
• Number Of Inputs: 16
• Number Of Outputs: 1
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Fully Programmable Serializer/Deserializer
with UART/I
register REG2 for both the MAX9257 and the MAX9258.
The four bits of REG2[7:4] select the divide ratio (STODIV)
for the STO clock as a function of the pixel clock (Table
24). The timeout period is determined by counter bits
REG2[3:0] that increment once every STO clock period.
Write to REG2[3:0] to determine the counter end time.
The STO counter counts to the programmed STOCNT +
1. The ECU must begin communicating before STO times
out, otherwise, the control channel closes (Figure 22). The
STO timeout period is given by:
For example:
If the pixel clock frequency is set to 16MHz, STODIV is
set to 1010 (STODIV = 1024), and STOCNT is set to
1001 (STOCNT = 9), the STO timer counts with
15.625kHz STO clock (16MHz/1024) internally until it
reaches 10 and timer expires. The t
1024 x 10 = 640µs.
The default value for STODIV is 1024 while the default
value for STOCNT is 0. That means the STO timeout
period is equal 1024 pixel clock cycles. Activity from
the ECU on the control channel shuts off the STO timer
and starts the ETO timer.
Figure 22. Control Channel Closing Due to STO Timeout
28
______________________________________________________________________________________
t
STO
=
VSYNC_IN
⎛
⎜
⎝
SDI/O±
DOUT_
f
CLK
CCEN
1
RX
TX
T1 = TIME TO ENTER CONTROL CHANNEL
T2 = STO TIMEOUT PERIOD
T3 = CONTROL CHANNEL EXIT TIME DUE TO STO
HSK = HANDSHAKING BETWEEN THE MAX9257 AND THE MAX9258
⎞
⎟ ×
⎠
STODIV
2
VIDEO
C Control Channel
×
(
T1
STOCNT
STO
is equal to t
+
1
)
T
x
T2
FROZEN
The ETO (end timeout) timer closes the control channel
if the ECU stops communicating for the ETO timeout
period. Configure register REG3[7:4] for both the
MAX9257 and the MAX9258 to select the divide ratio
(ETODIV) for the ETO clock as a function of the pixel
clock (Table 25). The timeout period is determined by
Table 25. ETO Clock Divide Ratio
REG3[7:4]
00XX
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
HSK
T3
VIDEO
ETODIV
16,384
32,768
1024
2048
4096
8192
128
256
512
16
16
32
64
ETO Timer