Motorola MPC8260 - Manual (Page 829)

29-49 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
Table 29-19. AAL1 Protocol-Specific RCT Field Descriptions
Offset Bits Name Description
0x0E 0Р7 С Reserved, should be cleared.
8 PFM Partially Þlled mode.
0 Partially Þlled cells mode is not used.
1 Partially Þlled 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 Þeld is speciÞed in the VOS (valid octet size) Þeld.
9 SRT Synchronous residual time stamp. Unstructured format only. The MPC8260 supports
clock recovery using an external SRTS PLL. The MPC8260 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 29.15,
ÒSRTS Generation and Clock Recovery Using External Logic.Ó)
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).
11 STF Structured format
0 Unstructured format is used.
1 Structured format is used.
12Р15 С Reserved, should be cleared.
0x10 0Ð3 SRTS_TMP 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.
4Р11 С Reserved, should be cleared.
12Ð15 SRTS
Device
Selects an SRTS device, whose address is SRTS_BASE[0Ð27] + SRTS Device[28Ð
31]. The 16 byte-aligned SRTS_BASE is taken from the parameter RAM.
0x12 0Р1 С Reserved, should be cleared.
2Ð7 VOS Valid octet size. SpeciÞes the number of valid octets from the beginning of the AAL1
user data Þeld. For unstructured, service values 1Ð47 are valid; for structured service,
values 1-46 are valid. Partially Þlled cell mode only.
8 SPV Structured pointer valid. Should be user-initialized user to zero. Structured format only.
9Ð15 SP Structured pointer. Used by the CP to calculate the structured pointer. This Þeld should
be initialized by the user to zero. Used in structured format only.
0x14 Ñ RBDCNT RxBD count. Indicates how may bytes remain in the current Rx buffer. Initialized with
MRBLR whenever the CP opens a new buffer.
0x16 0Р12 С Reserved, should be cleared.
13Ð15 SN Sequence number. Used by the CP to check incoming cellÕs sequence number.