GS1560A/GS1561 Data Sheet
3.8 DVB-ASI Functionality
The GS9060 conforms to DVB-ASI standard EN 50083-9:1998.
The GS1560A/GS1561 is said to be in DVB-ASI mode once the device has
detected 32 consecutive DVB-ASI words without a single word or disparity error
being generated. The device will remain in DVB-ASI mode until 32 consecutive
DVB-ASI word or disparity errors are detected, or until SMPTE TRS ID words have
been detected.
The lock detect block may also drop out of DVB-ASI mode under the following
conditions:
•
•
•
•
RESET_TRST is asserted LOW
CDx is HIGH
SMPTE_BYPASS is asserted HIGH in slave mode
DVB_ASI is asserted LOW in slave mode
K28.5 sync patterns in the received DVB-ASI data stream will be detected by the
device in either inverted or non-inverted form.
In master mode, the GS1560A/GS1561 sets the SMPTE_BYPASS pin LOW and
the DVB_ASI pin HIGH to indicate that it has locked to a DVB-ASI input data
stream. When operating in slave mode, the application layer must set the SD/HD
pin HIGH, in addition to setting SMPTE_BYPASS LOW and DVB_ASI HIGH, in
order to enable DVB-ASI operation.
3.8.1 Transport Packet Format
Transport packet structure shall conform to the specifications of EN/ISO/IEC
13818-1 and ETS 300 429 for Transport Stream Packets. The packet length can
be 188 or 204 bytes.
3.8.2 DVB-ASI 8b/10b Decoding and Word Alignment
After serial-to-parallel conversion, the internal 10-bit data bus is fed to the DVB-ASI
8b/10b decode and word alignment block. The function of this block is to word align
the data to the K28.5 sync characters, and 8b/10b decode and bit-swap the data
to achieve bit alignment with the data outputs.
The extracted 8-bit data will be presented to DOUT[17:10], bypassing all internal
SMPTE mode data processing.
NOTE: When operating in DVB-ASI mode, DOUT[9:0] are forced LOW.
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