Motorola PowerQUICC II MPC8280 Series Reference Manual page 1240

IMA Programming Model
34.4.4.1.2 IMA Group Transmit State (IGTSTATE)
The fields of the IGTSTATE register are shown in Figure 34-15.
0
Field TSTF
Figure 34-15. IMA Group Transmit State (IGTSTATE)
Table 34-7 describes the IGTSTATE bit fields.
Bits Name
0 TSTF TRL stuff flag. Microcode-managed parameter. Indicates that the next ICP cell on the TRL will
be part of a stuff event. Initialize to zero at group startup.
1 TIMSTF TRL imminent stuff flag. Microcode-managed parameter. Indicates that an upcoming stuff
event will be signalled in the next ICP of the TRL (via LSI=001). Initialize to zero at group
startup.
2 GTE Go to end flag - TRL has requested 2 times before round robin distribution has completed or
link will underrun and is still due a cell from round robin distribution. Microcode managed
parameter initialize to 0. Used for optional TRL Service Latency enhancement only.
3 TRQS TRL Request - TRL has requested therefore 1 round robin distribution of cells and is yet to be
completed. Microcode managed parameter initialize to 0. Used for optional TRL Service
Latency enhancement only.
4 ELX Early exit flag. Microcode-managed parameter. Initialize to zero at group startup.
5 — Reserved
6 ICH ICP change holdoff. Microcode-managed parameter. Initialize to zero at group startup.
7 ICPCA ICP change allowed flag. Microcode-managed parameter. See description of IGTCNTL[ICPC].
34.4.4.1.3 Transmit Group Order Table
The transmit group order table defines the order of the links in the round-robin distribution
of cells to the links of the IMA group. The table consists of an array of bytes ordered from
first link to last link, with each byte providing the PHY address of its associated link. The
end of the table is indicated by an entry programmed to 0x1F.
This table alone defines the order of cell distribution. It is the responsibility of software to
program the LID of the links in the IMA Link Table entries, and to program the group order
table such that its order corresponds to the order of increasing LIDs within the group.
The format of a transmit group order table entry is shown in Figure 34-16.
0
Field
Figure 34-16. Transmit Group Order Table Entry
34-30
Freescale Semiconductor, Inc.
1 2
TIMSTf GTE
Table 34-7. IGTSTATE Field Descriptions
2
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3 4 5
ELX —
TRQS
Description
3
PHY ADDRESS
6 7
ICH ICPCA
7
MOTOROLA