Freescale Semiconductor MPC8260 - Manual (Page 1074)

ATM AAL2
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
32-12 Freescale Semiconductor
0x02 0-11 — Reserved, should be cleared during initialization.
12 NoSTF No STF byte. See Section 32.3.4, “No STF Mode .”
0 Normal AAL2 cell structure.
1 The cell does not include the STF byte. In this mode each cell starts with
a new packet and contains only whole packets (no split or partial).
13–15 AAL AAL type
000 AAL0 —Segmentation 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
101 AAL1_CES. Refer to
Chapter 31, “ATM AAL1 Circuit Emulation
Service .”
All others reserved.
0x04 — — Reserved, should be cleared during initialization.
0x06 — — Reserved, should be cleared during initialization.
0x08 — — Reserved, should be cleared during initialization.
0x0A — FirstQueue Points to the first queue to be serviced in the transmitter cycle. In
round-robin priority mode (TCT[Fix]=0), this pointer could point to any one
of the TxQDs related to this channel. In fixed priority mode (TCT[Fix]=1),
this pointer should point to the highest priority TxQD.
0x0C 0–7 Rate Remainder Rate remainder. Used by the APC to hold the rate remainder after adding
the pace fraction to the additive channel rate. Should be cleared during
initialization by the user.
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 — Timer_CU_period Timer_CU duration in units of APC slots. Assures that CPS-Packet
already packed in a cell wait at most the Timer_CU duration. The user
defines this field.
0x12 — Timer_Period_Shadow This field must be initialized to the Timer_CU period in units of APC slots.
0x14 — — Reserved, should be cleared during initialization.
0x16 — APCLC APC linked channel. Used by the CP. Should be cleared during
initialization.
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.
Table 32-1. AAL2 Protocol-Specific Transmit Connection Table (TCT)
Field Descriptions (continued)
Offset Bits Name
1
Description