ATM Controller and AAL0, AAL1, and AAL5
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
30-54 Freescale Semiconductor
0x02 0 Internal use only. Should be cleared.
1 INF Used for AAL5 Only. Indicates the transmitter state. Initialize to 0
0 In idle state.
1 In AAL5 frame transmission state.
2–11 Internal use only. Should be cleared.
12 ABRF Used for AAL5 Only.
0 ABR Flow control is disabled.
1 ABR Flow control is enabled.
13–15 AAL AAL type
000 AAL0—Reassembly with no adaptation layer
001 AAL1—ATM adaptation layer 1 protocol
010 AAL5—ATM adaptation layer 5 protocol
100 AAL2—ATM adaptation layer 2 protocol. Refer to Chapter32, “ATM AAL2.”
101 AAL1_CES—Refer to Chapter 31, “ATM AAL1 Circuit Emulation Service.”
All others reserved.
0x04 TxDBPTR Tx data buffer pointer. Holds the real address of the current position in the Tx buffer.
0x08 TBDCNT Transmit BD count. Counts the remaining data to transmit in the current transmit buffer.
Its initial value is loaded from the data length field of the TxBD when a new buffer is
open; its value is subtracted for any transmitted cell associated with this channel.
0x0A — TBD_OffSe
t
Transmit BD offset. Holds offset from TBD_BASE of the current BD. Should be cleared
initially.
0x0C 0–7 Rate
Reminder
Rate remainder. Used by the APC to hold the rate remainder after adding the pace
fraction to the additive channel rate. Should be cleared initially.
8–15 PCR
Fraction
Peak cell rate fraction. Holds the peak cell rate fraction of this channel in units of 1/256
slot. If this is an ABR channel, this field is automatically updated by the CP.
0x0E PCR Peak cell rate. Holds the peak cell rate (in units of APC slots) permitted for this channel
according to the traffic contract. Note that for an ABR channel, the CP automatically
updates PCR to the ACR value.
0x10 — Protocol-specific
0x16 APCLC APC linked channel. Used by the CP. Initialize to 0 (null pointer).
0x18 ATMCH ATM cell header. Holds the full (4-byte) ATM cell header of the current channel. The
transmitter appends ATMCH to the cell payload during transmission.
Table30-21. TCT Field Descriptions (continued)
Offset Bits Name Description