CXD1948R Просмотр технического описания (PDF) - Sony Semiconductor
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CXD1948R Datasheet PDF : 78 Pages
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CXD1948R
5-3. Transport Stream Packet Split and Combine Functions
The CXD1948R supports split and combine functions in order to use the bus bandwidth effectively.
Concretely, the input transport stream packet can be split or combined according to the input rate and
transmitted as an isochronous packet.
The minimum size which can be split on the CXD1948R is one data block.
For DVB specifications, one data block consists of 24 bytes, which means that 1 packet can be divided into
eighths for transmission.
The maximum size which can be combined is 15 packets. However, if the number of packets which can be
transmitted in that cycle is smaller than the number that can be combined, all the packets present are
combined in the transmission FIFO buffer and transmitted.
The number of data blocks to be transmitted in one isochronous cycle is set before hand according to the
stream peak rate.
This is done by setting values in the CFR NOSP and NODB registers.
The number of transmit source packets in one isochronous cycle is expressed by NOSP, and the number of
transmit data blocks in one isochronous cycle is expressed by NODB.
The default values are NOSP = 0001 and NODB = 000, for transmission of one source packet in one
isochronous cycle. Always be sure to set either NOSP or NODB to 0.
If the isochronous transmission parameters are not set such that the transmission rate is greater than the input
stream peak rate, the FIFO buffer may fail.
Example of Isochronous Transmit using Packet Split and Combine Functions
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