Freescale Semiconductor MPC8260 - Manual (Page 1045)

ATM AAL1 Circuit Emulation Service
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 31-29
Table 31-6 describes AAL1 CES protocol-specific RCT fields.
Offset + 0x16 Block Size — SN
Offset + 0x18 Super Channel Number RXBM SLIPIM — CASBS
Table 31-6. AAL1 CES Protocol-Specific RCT Field Descriptions
Offset Bits Name Description
0x0E 0–3 SRTS_DEV Selects an SRTS device, whose address is SRTS_BASE[0–27] + SRTS_DEV[28–31].
The 16 byte-aligned SRTS_BASE is taken from the parameter RAM.
4–7 — Reserved, should be cleared during initialization.
8 PFM Partially filled mode.
0 Partially filled cells mode is not used.
1 Partially filled cells mode is used. The receiver copies only valid octets from the AAL1
cell to the Rx buffer. The number 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 clock recovery using an external SRTS PLL. The PowerQUICC II tracks the
SRTS from the incoming four cells with SN = 1, 3, 5, and 7 and writes it to the external
SRTS device. Every eight cells the CP writes a valid SRTS to external logic. (See
Section 30.15, “SRTS Generation and Clock Recovery Using External Logic .”)
0 SRTS mode is not used.
1 SRTS mode is used.
10 INVE Inverted empty.
0 RxBD[E] is interpreted normally (1 = empty, 0 = not empty).
1 RxBD[E] is handled in negative logic (0 = empty, 1 = not empty).
Note that in CAS mode (CESM=1) this bit must be set by the user; see
Section 31.4.1,
“Automatic Data Forwarding .”
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. Only non P-format AAL1 cells are received. The receiver does not
check the AAL1 structured pointer because there is no need to when the block size is one.
12-15 — Reserved, should be cleared during initialization.
0x10 0–3 OCASB/SR
TS_TMP OCASB applies when in CAS mode. Outgoing CAS Block. Points to one of the eight
available internal CAS blocks. The starting address of the table is
OUT_CAS_BLOCK_BASE+OCASB¥ 32. See
Section 31.4.7.1, “CAS Routing Table ” for
more details.
Note that the RCT and TCT use the same CAS routing table (CRT).
SRTS_TMP applies when not in CAS mode. Used by the CP to store the received SRTS
code. After a cell with SN = 7 is received, the CP writes the SRTS code to the external
SRTS device.
Note that when the receiver is in hunt mode SRTS information is not updated.
4–9 — Reserved, should be cleared during initialization.
10–15 VOS Valid octet size. 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. Partially filled cell mode only.
Figure 31-22. AAL1 CES Protocol-Specific RCT