dss-146
B0
B1
B2
B3
B4
B5
B6
B7
VC
DT
Data type
(DT)
Virtual channel
(VC)
Data identifier (DI) byte
dss-147
Channel
detect
V
irtual channel control
Data in
Channel identifier
Channel configuration
Channel 0
Channel 1
Channel 2
Channel 3
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Display Subsystem Environment
7.2.2.4.3 Data Identifier
The data identifier byte contains the virtual VC ID value and the DT value, as shown in
. The
VC ID is contained in the 2 MSBs of the data identifier byte. The DT value is contained in the 6 LSBs of
the data identifier byte. DI[7:6]: These 2 bits identify the data as directed to one of four VCs. DI[5:0]:
These six bits specify the DT.
Figure 7-46. Data Identifier Structure
7.2.2.4.4 Virtual Channel ID - VC Field, DI[7:6]
The host can service up to four peripherals with tagged commands or blocks of data using the VC ID field
of the header for packets targeted at different peripherals. The VC ID enables one serial stream to service
two or more virtual peripherals by multiplexing packets onto a common transmission channel. Note that
each packet sent in a single transmission have its own VC assignment and can be directed to different
peripherals. The VC ID is defined in the DSS.
and
registers for short and long packets, respectively. It should not
be modified by hardware. There is one set of registers for each VC. Each set of registers defines the
characteristics of the traffic between the host and the display associated with the VC.
shows the VC controller.
Figure 7-47. Virtual Channel Controller
7.2.2.4.5 Data Type Field DT[5:0]
The DT field specifies whether the packet is a long or short packet type and the packet format. The DT
field, along with the word count field for long packets, informs the receiver on how many bytes to expect in
the remainder of the packet. This is necessary because there are no special packet start/end sync codes
to indicate the beginning and end of a packet. This permits packets to convey arbitrary data, but it also
requires the packet header to explicitly specify the size of the packet.
7.2.2.4.6 Pixel Data Formats in Video Mode
The host can send different pixel formats in video mode.
summarizes the pixel formats
supported by the DSI interface in video mode.
1599
SWPU177N – December 2009 – Revised November 2010
Display Subsystem
Copyright © 2009–2010, Texas Instruments Incorporated