Motorola PowerQUICC II MPC8280 Series Reference Manual page 1152

Receive and Transmit Connection Tables (RCT, TCT)
Table 32-6. AAL1 CES Protocol-Specific RCT Field Descriptions (continued)
Offset Bits Name
0x14 — RBDCNT
0x16 0–11 Block Size
12 —
13–15 SN
0x18 0-7 SCN
8 RXBM
9 SLIPIM
10-11 —
12-15 CASBS
32-32
Freescale Semiconductor, Inc.
RxBD count. Indicates how many bytes remain in the current Rx buffer. Initialized with
MRBLR whenever the CP opens a new buffer.
Used only in structured format. Specifies the structured block size (Block Size = 0xFFF =
4 Kbytes maximum).
Note that when working in CAS mode (CESM=1 and CASM=1), the block size should be
programmed to the superframe block size plus the size of the CAS block. However, when
working in basic mode (CES without CAS: CESM=1 and CASM=0) the block size should
be programmed to the number of MCC slots (Nx64) per frame assigned to this channel.
Reserved, should be cleared during initialization.
Sequence number. Used by the CP to check incoming cell's sequence number.
Super Channel Number.
This field should contain the MCC Super Channel Number that mapped to this ATM
channel. This field must be initialized by the user in CES mode only. See
Section 32.4.7, "Mapping VC Signaling to CAS Blocks."
Receive buffer interrupt mask
0 The receive buffer event of this channel is disabled. (The event is not sent to the
interrupt queue.)
1 The receive buffer event of this channel is enabled.
Slip interrupt mask
0 The slip interrupts SLIPS and SLIPE are both masked.
1 When the receiver switches to hunt mode due to a 3-step-SN algorithm fault, or due to
two successive mismatched pointers, or due to a pre-overrun condition, the SLIPS
interrupt is sent to the interrupt queue. See Section 32.6, "3-Step-SN Algorithm," and
Section 32.13, "AAL1 CES Exceptions." When the receiver resynchronizes, SLIPE
interrupt is sent to the interrupt queue. Note that this is the error reporting mechanism
during automatic data forwarding (ATM-to-TDM bridging).
Reserved, should be cleared during initialization.
CAS block size.This field contains the number divided by two (N/2) of signaling nibbles
mapped to this ATM channel. See Section 32.4.7, "Mapping VC Signaling to CAS
Blocks."
Note that if the number of signaling nibbles is odd, this field should be programmed to
(N+1)/2. See Section 32.2.2, "Signaling Path."
Example: ESF with three T1 time slots connected to one ATM channel. The Data_Size
= 3*24 = 72 octets and the CAS Block= 2 octets (N=3, (N+1)/2 = 2), so in this case
the Block_Size = 72+2 = 74
MPC8280 PowerQUICC II Family Reference Manual
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