DS90UH947-Q1 Datasheet, PDF (30/87 Pages) Texas Instruments – 1080p OpenLDI to FPD-Link III Serializer with HDCP

DS90UH947-Q1
SNLS455 – NOVEMBER 2014
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Normal
Step 1: DES in BIST
BIST
Wait
Step 2: Wait, SER in BIST
BIST
start
Step 3: DES in Normal
Mode - check PASS
BIST
stop
Step 4: DES/SER in Normal
Figure 28. BIST Mode Flow Diagram
8.3.15.2 Forward Channel And Back Channel Error Checking
While in BIST mode, the serializer stops sampling the FPD-Link input pins and switches over to an internal all
zeroes pattern. The internal all-zeroes pattern goes through scrambler, DC-balancing, etc. and is transmitted
over the serial link to the deserializer. The deserializer, on locking to the serial stream, compares the recovered
serial stream with all-zeroes and records any errors in status registers. Errors are also dynamically reported on
the PASS pin of the deserializer.
The back-channel data is checked for CRC errors once the serializer locks onto the back-channel serial stream,
as indicated by link detect status (register bit 0x0C[0] - Table 10). CRC errors are recorded in an 8-bit register in
the deserializer. The register is cleared when the serializer enters BIST mode. As soon as the serializer enters
BIST mode, the functional mode CRC register starts recording any back channel CRC errors. The BIST mode
CRC error register is active in BIST mode only and keeps a record of the last BIST run until cleared or the
serializer enters BIST mode again.
BISTEN
(DES)
TxCLKOUT±
TxOUT[3:0]±
DATA
(internal)
PASS
Prior Result
PASS
DATA
X
(internal)
PASS Prior Result
Normal
PRBS
X = bit error(s)
X
X
BIST Test
BIST Duration
FAIL
BIST
Result
Held
Normal
Figure 29. BIST Waveforms, in Conjunction with Deserializer Signals
8.3.16 Internal Pattern Generation
The DS90UH947-Q1 serializer provides an internal pattern generation feature. It allows basic testing and
debugging of an integrated panel. The test patterns are simple and repetitive and allow for a quick visual
verification of panel operation. As long as the device is not in power down mode, the test pattern will be
displayed even if no input is applied. If no clock is received, the test pattern can be configured to use a
programmed oscillator frequency. For detailed information, refer to Application Note AN-2198.
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