User manual

ATM AAL2
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
32-14 Freescale Semiconductor
Table 32-2 describes the CPS TxQD fields.
.
0 7 8 9 10 11 12 13 15
Offset + 0x00 — BNM SW HEC CPS TBM —
Offset + 0x02 TxBD Table Offset In (switched mode only)
Offset + 0x04 TxBD Table Base
Offset + 0x06
Offset + 0x08 TxBD Table Offset Out
Offset + 0x0A Number of Packets In Queue
Offset + 0x0C NextQueue
Offset + 0x0E —
Figure 32-7. CPS Tx Queue Descriptor (TxQD)
Table 32-2. CPS TxQD Field Descriptions
Offset Bits Name
1
Description
0x00 0-7 — Reserved for internal use. (Used to save the BD status of the open BD.)
8 BNM Buffer not-ready interrupt mask of the TxBD table.
0 The transmit buffer-not-ready event for this queue is masked. (The event is not sent
to the interrupt queue.)
1 The buffer-not-ready event for this queue is enabled.
9 SW Switching queue.
0 Normal TX Queue.
1 This TxQD handles a switching queue. The receiver and transmitter share this queue.
10 HEC HEC calculation.
0 Transmitter calculates the CPS header HEC.
1 The CPS header HEC is taken as is from the CPS buffer descriptor.
11 CPS Sublayer type. For a CPS TxQD, this field must be set.
0 SSSAR or SSTED.
1 CPS packet.
12 TBM Transmit buffer interrupt mask.
0 The transmit buffer event of this queue is masked. (The event is not sent to the
interrupt queue).
1 The transmit buffer event of this queue is enabled.
13-15 — Reserved, should be cleared during initialization.
0x02 — TxBD Table
Offset In
Used only when this queue is used for switching (SW=1). Should be cleared during
initialization.
0x04 — TxBD Table
Base
This pointer points to the base address of the BD table.
0x08 — TxBD Table
Offset Out
Holds the offset from the TxBD table base to the next BD to be opened by the
transmitter. Should be cleared during initialization.