Freescale Semiconductor MPC8260 PowerQUICC II Family Reference Manual page 974

ATM Controller and AAL0, AAL1, and AAL5
Offset Bits Name
0x02 0 —
1 INF
2–11 —
12 ABRF
13–15 AAL
0x04 — TxDBPTR
0x08 — TBDCNT
0x0A — TBD_OffSe
0x0C 0–7 Rate
Reminder
8–15 PCR
Fraction
0x0E — PCR
0x10 — —
0x16 — APCLC
0x18 — ATMCH
30-54
Table 30-21. TCT Field Descriptions (continued)
Internal use only. Should be cleared.
Used for AAL5 Only. Indicates the transmitter state. Initialize to 0
0 In idle state.
1 In AAL5 frame transmission state.
Internal use only. Should be cleared.
Used for AAL5 Only.
0 ABR Flow control is disabled.
1 ABR Flow control is enabled.
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
101 AAL1_CES—Refer to
All others reserved.
Tx data buffer pointer. Holds the real address of the current position in the Tx buffer.
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.
Transmit BD offset. Holds offset from TBD_BASE of the current BD. Should be cleared
t initially.
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.
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.
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.
Protocol-specific
APC linked channel. Used by the CP. Initialize to 0 (null pointer).
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.
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Description
Chapter 31, "ATM AAL1 Circuit Emulation
Chapter 32, "ATM AAL2."
Service."
Freescale Semiconductor