![](http://datasheet.mmic.net.cn/390000/TSB42AA4I_datasheet_16839080/TSB42AA4I_162.png)
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6.7.1
TXDP Header Register Descriptions
The TXDP header registers have meaning only when the associated transmit path is being used in header
insert mode. The header fields for various 1394 and video mode specific formats are provided via these
registers. The default values for these registers match the default stream types for the data buffers. If the
data buffer stream type is changed from the default configuration, then the TXDP header registers must be
programmed to reflect the new stream type. All RW bits in these registers must be configured by software
to the appropriate mode specific values. All RU registers can be made writeable by setting the
TXDP(N)CFG.VHFWEN bit to 1.
0x254 0x26C 0x284 0x29C 0x2B4 0x2CC 0x2E4 0x2FC
TXDP(N)H0 – When associated buffer is configured for stream type 1 (Async)
DEFAULT CONFIGURATION FOR BUFFER 4
BIT
NAME
TYPE
RESET
FUNCTION
31:18
RSVD
R0
0
Reserved – A write to this location has no effect. A read returns 0s.
17:16
SPD
RW
0
Speed code – This 2-bit value represents the IEEE-1394 speed code to
be provided in the header of the transmitted packet.
15:10
TLABEL
RW
0
Transaction label – This 6-bit value contains the IEEE-1394 transaction
label to be provided in the header of the transmitted packet.
9:8
RT
RW
0
Retry code – This two-bit value contains the IEEE-1394 retry code to be
provided in the header of the transmitted packet.
7:4
TCODE
RW
0
Transaction code This 4-bit value contains the IEEE-1394 transaction
code to be provided in the header of the transmitted packet.
3:0
PRIORITY
RW
0
Priority – This 4-bit field contains the IEEE-1394 priority value to be
provided in the header of the transmitted packet transmitted packet.
TXDP(N)H0 – When associated buffer is configured for stream types: 3 ( Async Streams)
DEFAULT CONFIGURATION FOR BUFFER 2
BIT
NAME
TYPE
RESET
FUNCTION
31:16
DATALENGTH
RW
0
Data length – This field represents the data_length to be provided in the
header of the transmitted packet.
15:14
TAG
RW
0
TAG – This field contains the TAG value to be provided in the header of
the transmitted packet.
13:8
CHANNUM
RW
0
Channel number – This field contains the channel number to be
provided in the header of the transmitted packet.
7:6
RSVD
R0
0
Reserved A write to this location has no effect. A read returns 0s.
5:4
SPD
RW
0
Speed code – This field contains the speed code to be used for the
transmitted packet.
3:0
SYNC CODE
RW
0
Synchronization code – This field contains the synchronization code to
be provided in the header of the transmitted packet.