DS90UR916Q_13 Datasheet, PDF (28/45 Pages) Texas Instruments – 5 - 65 MHz 24-bit Color FPD-Link II Deserializer with Image Enhancement

DS90UR916Q
SNOSB46E – MARCH 2011 – REVISED APRIL 2013
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Step 1: Place the DS90UR905 Ser in BIST Mode by setting Ser BISTEN = H. For the DS90UR905 Ser or
DS99R421 FPD-Link II Ser BIST Mode is enabled via the BISTEN pin. For the DS90C241 Ser or DS90UR241
Ser, BIST mode is enetered by setting all the input data of the device to Low state. A PCLK is required for all the
Ser options. When the Des detects the BIST mode pattern and command (DCA and DCB code) the RGB and
control signal outputs are shut off.
Step 2: Place the DS90UR916Q Des in BIST mode by setting the BISTEN = H. The Des is now in the BIST
mode and checks the incoming serial payloads for errors. If an error in the payload (1 to 24) is detected, the
PASS pin will switch low for one half of the clock period. During the BIST test, the PASS output can be
monitored and counted to determine the payload error rate.
Step 3: To Stop the BIST mode, the Des BISTEN pin is set Low. The Des stops checking the data and the final
test result is held on the PASS pin. If the test ran error free, the PASS output will be High. If there was one or
more errors detected, the PASS output will be Low. The PASS output state is held until a new BIST is run, the
device is RESET, or Powered Down. The BIST duration is user controlled by the duration of the BISTEN signal.
Step 4: To return the link to normal operation, the Ser BISTEN input is set Low. The Link returns to normal
operation.
Figure 26 shows the waveform diagram of a typical BIST test for two cases. Case 1 is error free, and Case 2
shows one with multiple errors. In most cases it is difficult to generate errors due to the robustness of the link
(differential data transmission etc.), thus they may be introduced by greatly extending the cable length, faulting
the interconnect, reducing signal condition enhancements (De-Emphasis, VODSEL, or Rx Equalization).
Normal
Step 1: SER in BIST
BIST
Wait
Step 2: Wait, DES in BIST
BIST
start
Step 3: DES in Normal
Mode - check PASS
BIST
stop
Step 4: SER in Normal
Figure 25. BIST Mode Flow Diagram
BER Calculations
It is possible to calculate the approximate Bit Error Rate (BER). The following is required:
• Pixel Clock Frequency (MHz)
• BIST Duration (seconds)
• BIST test Result (PASS)
The BER is less than or equal to one over the product of 24 times the PCLK rate times the test duration. If we
assume a 65MHz PCLK, a 10 minute (600 second) test, and a PASS, the BERT is ≤ 1.07 X 10E-12
The BIST mode runs a check on the data payload bits. The LOCK pin also provides a link status. It the recovery
of the C0 and C1 bits does not reconstruct the expected clock signal, the LOCK pin will switch Low. The
combination of the LOCK and At-Speed BIST PASS pin provides a powerful tool for system evaluation and
performance monitoring.
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