Freescale Semiconductor MPC8260 - Manual (Page 1050)

ATM AAL1 Circuit Emulation Service
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
31-34 Freescale Semiconductor
31.9.2.1 AAL1 CES Protocol-Specific TCT
Figure 31-24 shows the AAL1 CES protocol-specific transmission connection tables (TCT).
Table 31-8 describes AAL1 CES protocol-specific TCT fields.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Offset + 0x10 — Valid Octet Size (VOS) PFM SRT SPIF STF — SN
Offset + 0x12 SRTS_DEV Block Size
Offset + 0x14 ICASB/SRTS_TMP Structured Pointer (SP)
Figure 31-24. AAL1 CES Protocol-Specific TCT
Table 31-8. AAL1 CES Protocol-Specific TCT Field Descriptions
Offset Bits Name Description
0x10 0-1 — Reserved, should be cleared during initialization.
2–7 VOS Valid octet size. Partially filled cell mode only. Specifies the number of valid octets from
the beginning of the AAL1 user data field. For unstructured service, values 1-47 are
valid; for structured service, values 1-46 are valid.
8 PFM Partially filled mode.
0 Partially filled cells mode is not used.
1 Partially filled cells mode is used. The transmitter copies only valid octets from the
buffer to the AAL1 cell. The size of the valid octets from the beginning of the AAL1
user data field is specified in the VOS (valid octet size) field.
9 SRT Synchronous residual time stamp. Unstructured format only. The PowerQUICC II
supports SRTS generation using external logic. If this mode is enabled, the
PowerQUICC II reads the SRTS from external logic and inserts it into four cells for
which SN = 1, 3, 5, or 7. The PowerQUICC II reads the new SRTS from external logic
every eight cells. (See
Section , “ .”)
0 SRTS mode is not used.
1 SRTS mode is used.
10 SPIF Structured pointer inserted flag. Indicates that a structured pointer has been inserted
in the current cycle. The user should initialize this field to zero. Used by the CP only.
11 STF Structured format.
0 Unstructured format is used.
1 Structured format is used.
Note that although the structured format may be used, if the block size is one, the user
should clear STF so that only non P-format AAL1 cells are generated.
12 — Reserved, should be cleared during initialization.
13–15 SN Sequence number field. Used by the CP to check the incoming cells SN. Initialize to 0.
0x12 0–3 SRTS_DEV Used to select a SRTS device. The SRTS device address is
SRTS_BASE[0–27]+SRTS_DEV[28:31]. SRTS_BASE is taken from the parameter
RAM and is 16-byte aligned.
4–15 Block Size 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.