Freescale Semiconductor MPC8260 - Manual (Page 1049)

ATM AAL1 Circuit Emulation Service
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 31-33
0x02 0-12 — Reserved, should be cleared during initialization.
13–15 AAL AAL type
000 AAL0 —Reassembly with no adaptation layer
001 AAL1 —ATM adaptation layer 1
010 AAL5 —ATM adaptation layer 5.
100 AAL2 —ATM adaptation layer 2. Refer to
Chapter 32, “ATM AAL2 .”
101 AAL1_CES —ATM adaptation layer 1 with 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_Offset Transmit BD offset. Holds offset from TBD_BASE of the current BD. Initialize to 0.
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. Initialize to 0.
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.
0x1C 0–1 — Reserved, should be cleared during initialization.
2–7 PMT Performance monitoring table. Points to one of the available 64 performance monitoring
tables. The starting address of the table is PMT_BASE+PMT
× 32. Can be changed
on-the-fly.
8–15 TBD_BASE TxBD base. Points to the first BD in the channel’s TxBD table. The 8 most-significant
bits of the address are taken from BD_BASE_EXT in the parameter RAM. The four
least-significant bits of the address are taken as zero.
0x1E 0–11
12 BNM Buffer-not-ready interrupt mask. Can be changed on-the-fly.
0 The transmit buffer-not-ready event of this channel is masked. (TBNR event is not
sent to the interrupt queue.)
1 The buffer-not-ready event of this channel is enabled.
13 STPT Stop transmit. Initialize to 0. When the host sets this bit, the CP deactivates this channel
and clears TCT[VCON] when the channel is next encountered in the APC scheduling
table. Note that for AAL5 if STPT is set and frame transmission is already started
(TCT[INF]=1), an abort indication will be sent (last cell with zero length field).
14 IMK Interrupt mask. Can be changed on-the-fly.
0 The transmit buffer event of this channel is masked. (TXB event is not sent to the
interrupt queue.)
1 The transmit buffer event of this channel is enabled.
15 PM Performance monitoring. Can be changed on-the-fly.
0 No performance monitoring for this VC.
1 Performance is monitored for this VC. When a cell is sent for this VC, the performance
monitoring table indicated in PMT field is updated.
Table 31-7. TCT Field Descriptions (continued)
Offset Bits Name Description