DS90UB901Q_15 Datasheet, PDF (33/50 Pages) Texas Instruments – 10 - 43MHz 14 Bit Color FPD-Link III Serializer and Deserializer with Bidirectional Control Channel

DS90UB901Q, DS90UB902Q
www.ti.com
SNLS322E – JUNE 2010 – REVISED APRIL 2013
The BIST duration is defined by the width of BISTEN. BIST starts when Deserializer LOCK goes HIGH and
BISTEN is set HIGH. BIST ends when BISTEN goes LOW. Any errors detected after the BIST Duration are not
included in PASS logic.
Note: AT-SPEED BIST is only available in the Camera mode and not the Display mode
The following diagram shows how to perform system AT SPEED BIST:
Serializer MODE = 0 and Deserializer MODE = 1
Apply power for Serializer and Deserializer
Normal
Step 1: Enable AT SPEED BIST by placing the
Deserializer in BIST by mode setting BISTEN = H
Step 4: Place System in
Normal Operating Mode
BISTEN = L
BIST Wait
Step 2: Deserializer will setup Serializer and enable BIST
mode through Bidirectional control channel
communication and then reacquire forward channel clock
BIST Start
Step 3: Stop AT SPEED BIST by turning off BIST
mode with BISTEN = L at the Deserializer.
BIST Stop
Figure 34. AT-SPEED BIST System Flow Diagram
Step 1: Place the Deserializer in BIST Mode.
Serializer and Deserializer power supply must be supplied. Enable the AT SPEED BIST mode on the
Deserializer by setting the BISTEN pin High. The 902 GPIO[1:0] pins are used to select the PCLK frequency of
the on-chip oscillator for the BIST test on high speed data path.
Des GPIO[1:0]
00
01
10
11
Table 5. BIST Oscillator Frequency Select
Oscillator Source
External PCLK
Internal
Internal
Internal
min (MHz)
10
typ (MHz)
50
25
12.5
max (MHz )
43
The Deserializer GPIO[1:0] set to 00 will bypass the on-chip oscillator and an external oscillator to Serializer
PCLK input is required. This allows the user to operate BIST under different frequencies other than the
predefined ranges.
Step 2: Enable AT SPEED BIST by placing the Serializer into BIST mode.
Deserializer will communicate through the bidirectional control channel to configure Serializer into BIST mode.
Once the BIST mode is set, the Serializer will initiate BIST transmission to the Deserializer.
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