Freescale Semiconductor MPC8260 - Manual (Page 1073)

ATM AAL2
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 32-11
Table 32-1. AAL2 Protocol-Specific Transmit Connection Table (TCT)
Field Descriptions
Offset Bits Name
1
Description
0x00 0–1 — Reserved, should be cleared during initialization.
2 GBL Global. Setting GBL enables snooping of data buffers, BD, interrupt
queues and free buffer pool.
3–4 BO Byte ordering. This field is used for data buffers.
00 Reserved.
01 Power PC little endian.
1x Big endian.
5 — Reserved, should be cleared during initialization.
6 DTB Data buffer bus selection.
0 Data buffers reside on the 60x bus.
1 Data buffers reside on the local bus.
7 BIB Bus selection for the BDs, interrupt queues and the free buffer pool.
0 Reside on the 60x bus.
1 Reside on the local bus.
8 AVCF Auto VC off. Determines APC behavior when the last buffer associated
with this VC has been sent and no more buffers are in the VC’s TxBD
table,
0 The APC does not remove this VC from the schedule table and
continues to schedule it to transmit.
1 The APC removes this VC from the schedule table. To continue
transmission after the host adds buffers for transmission, a new ATM
TRANSMIT command is needed, which can be issued only after the CP
clears the VCON bit. (Bit 13)
9 PFM Partial fill mode. See Section 32.3.3, “Partial Fill Mode (PFM) .”
0 Partially filled cells are not supported.
1 Partially filled cells are supported.
10-11 ATT ATM traffic type
00 Peak cell-rate pacing (regular traffic). The host must initialize PCR
and PCR fraction. Other traffic parameters are not used.
01 Peak and sustain cell rate pacing (VBR traffic). The APC performs a
continuous-state leaky bucket algorithm (GCRA) to pace the
channel-sustain cell rate. The host must initialize PCR, PCR fraction,
SCR, SCR fraction, and BT (burst tolerance).
10 Peak and Minimum cell rate pacing. The host must initialize PCR, PCR
fraction, MCR, MCR fraction, and MDA.
11 Reserved.
12 ET Enable Timer_CU.
0 Timer_CU operation in this channel is disabled.
1 Timer_CU operation in this channel is enabled.
13 VCON Virtual channel is on
Should be set by the host before it issues an
ATM TRANSMIT command.
When the host sets the STPT (stop transmit) bit, the CP deactivates this
channel and clears VCON. The host can issue another
ATM TRANSMIT
command only when the CP clears VCON.
14–15 INTQ Points to one of the four interrupt queues available.