![](http://datasheet.mmic.net.cn/390000/TSB42AA4I_datasheet_16839080/TSB42AA4I_77.png)
512
5.4.2
Asynchronous Stream Receive
Asynchronous stream packets are received at buffers with streamtype defined as asynchronous stream.
The packet control token gives information about the received packet. For asynchronous stream packets,
this quadlet is included with the data in the data buffer according to the RXDPB(N)CFG0.INSERTPKTTO-
KEN bit. The packet control token format for asynchronous stream packets is shown in Figure 55.
TAG
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
31
ISOCHRONOUSDATA
SYNC
CODE
TCODE
0
CHANNUM
DATALENGTH
1
1
0
DATASIZE
RSVD
ERRCODE
S
P
R
PAD
SPD
RSVD
Figure 510. Asynchronous Stream Receive Format
Table 513. Asynchronous Stream Receive Functions
FIELD NAME
DESCRIPTION
RSVD
Reserved
DATASIZE
Packet control token - Size of the packet in quadlets
S
Packet control token - This bit is set to 1 whenever the packet control token is attached to a
self-ID packet.
P
Packet control token - This bit is set to 1 whenever the packet control token is attached to a
PHY packet.
RSVD
Reserved
ERRCODE
Packet control token - This 5-bit field holds the error code. 0_0001 corresponds to complete.
0_1101 corresponds to a data error.
PAD
Packet control token - Number of padding bytes added.
SPD
Packet control token - The spd field indicates the speed at which the current packet was sent.
00 = 100 Mbits/s, 01 = 200 Mbits/s, 10 = 400 Mbits/s, and 11 is undefined for this
implementation.
RSVD
Reserved
DATALENGTH
The dataLength field indicates the number of bytes in the current packet.
TAG
The TAG field indicates the format of data carried by isochronous packet
(00 = unformatted, 01 11 are reserved).
CHANNUM
The CHANNUM field contains the channel number with which this data is associated.
TCODE
The TCODE field carries the transaction code for the current packet (TCODE = 0xA).
SYNC CODE
The SYNC CODE field carries the transaction layer-specific synchronization bits.
ISOCHRONOUSDATA
The packet data
5.5
Isochronous Data
ceLynx can be configured to transmit and receive several different types of isochronous data. These include
MPEG2 data, DirecTV data, and DV data.
The ceLynx can be configured to insert all isochronous transmit headers automatically, including headers
for MPEG2 and DV. In this case, only the raw isochronous data should be supplied to the HSDI or MCIF.
The header insertion is controlled in the TXDP(N)CFG registers for the associated data buffer. The
microcontroller can program the header values in the TXDP(N)H0TXDP(N)H4 registers for the associated
data buffer. For example, for MPEG2 data, the ceLynx can automatically insert the 1394 isochronous