Datasheet

TSB12LV32 Data Formats
75
SGLS139B − October 2003 − Revised April 2004 TSB12LV32-EP
Table 7−5. Isochronous Transmit Functions
FIELD NAME DESCRIPTION
dataLength The dataLength field indicates the number of bytes in the current packet.
TAG The TAG field indicates the format of data carried by the isochronous packet (00 = formatted, 01−11 are reserved).
chanNum The chanNum field carries the channel number with which the current data is associated.
tCode The transaction code for the current packet (tCode = Ah).
sy The sy field carries the transaction layer-specific synchronization bits.
isochronous data The isochronous data field contains the data to be sent with the current packet. The first byte of data must appear in byte 0 of
the first quadlet of this field. If the last quadlet does not contain four bytes of data, the unused bytes should be padded with
zeros.
7.2.1 Isochronous Receive (TSB12LV32 to Microcontroller Interface/Data-Mover Port)
The format of the isochronous receive data through the DM is shown in Figure 7−8 and is described in
Table 7−6. The data length, which is found in the header of the packet, determines the number of bytes in an
isochronous packet. The final packet after the isochronous data contains packet reception information. For
iscohronous receive through the general receive FIFO, the quadlet containing packet reception information
(trailer) is inserted as the first quadlet in the receive data, as shown in Figure 7−8.
3210 765411109815141312 19181716 20 21 31302928272625242322
isochronous data
sy
tCode (A)
TAGdataLength
chanNum
spdnumofQuadlets00 00 0 errCode 00 0000
Figure 7−8. Data-Mover Isochronous Receive Format
3210 765411109815141312 19181716 20 21 31302928272625242322
spdnumofQuadlets
00 000
errCode
00 0000
sy
tCode (A)
chanNum
dataLength
isochronous data
TAG
Figure 7−9. GRF Isochronous Receive Format
Table 7−6. Isochronous Receive Functions
FIELD NAME DESCRIPTION
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 = formatted, 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 = Ah).
sy The sy field carries the transaction layer-specific synchronization bits.
isochronous data The isochronous data field has the data to be sent with the current packet. The first byte of data must appear in byte 0 of the
first quadlet of this field. The last quadlet should be padded with zeros.
spd The spd field indicates the speed at which the current packet was sent.
numofQuadlets Total number of quadlets in the current packet (payload and header quadlets only).
errCode The errCode field indicates whether the current packet has been received correctly. The possibilities are Complete, DataErr,
or CRCErr, and have the same encoding as the corresponding acknowledge codes.