mt90502ag2 Zarlink Semiconductor, mt90502ag2 Datasheet - Page 53

• Manufacturer Part Number: mt90502ag2
• Description: Multi-channel Aal2 Sar
• Manufacturer: Zarlink Semiconductor

2.4.2
Once cells are received by the RX SAR, they are broken down into their component CPS-Packets, and analysed on
a per-CID basis. The RX SAR contains 255 RX CID descriptor structures per VC, each one indicating where
CPS-Packets containing that CID should be routed. Each CPS-Packet can be treated either as a PCM channel, an
HDLC channel, a CPU CPS-Packet, or it can be discarded entirely. This routing is based on the UUI of the
CPS-Packet.
The CPS-Packet Disassembly Structure field indicates for PCM and HDLC channels the CPS-Packet disassembly
structure to be used for CPS-Packets identified by the CID Descriptor Structure. UUIs 0 to 15 are routed together
because the 4 LSBs of the UUI can be used as a sequence counter. The remaining 16 UUIs are routed separately.
Each one can be destined to the CPU, to the PCM or HDLC channel, or deleted entirely.
2.4.3
CPS-Packets routed to PCM or HDLC channels are treated by the CPS-Packet disassembly structure. Though the
CPS-Packet disassembly structure is in the same location for PCM and HDLC channels, the fields are interpreted
as one or the other depending on the value of the appropriate UUI field in the corresponding CID descriptor
structure. The fields in the CPS-Packet disassembly structure indicate the form of the channel and the type of
treatment required on the CPS-Packet to be disassembled.
+1FE800h
+1FF000h
+1FF800h
+01800h
+02000h
The RX CID Structures are located in
SDRAM.
Each structure is 2048-bytes in size.
+00000h
+00800h
+01000h
CID Structure
CPS-Packet Disassembly Structures
Reserved
VC Number 1021
VC Number 1022
VC Number 1023
VC Number 0
VC Number 1
VC Number 2
VC Number 3
VC Number 4
Fields in Plain are written to by the CPU/Software.
CPS-Packet Disassembly Structure Number: Points to the CPS-Packet disassembly
structure to which all PCM or HDLC packets on this CID belong.
UUIx: Determines the destination of any CPS-Packet with the corresponding UUI.
“00”=delete; “01”=CPU packets, sent to RX CPU CPS-Packet buffer; “10”=PCM;
“11”HDLC.
+0h
+2h UUI31
+4h UUI23
+6h
Figure 23 - RX CID Structure
b15 b14 b13 b12 b11 b10 b9 b8
Zarlink Semiconductor Inc.
RX CID Structure
MT90502
UUI30
UUI22
53
+7E8h
+7F0h
+7F8h
+008h
+010h
+00h
UUI0-15
UUI29
UUI21
RX CID Descriptor Structure
UUI28
UUI20
CID Descriptor 253
CID Descriptor 254
CID Descriptor 255
CPS-Packet Dis. Structure Number [9:0]
CID Descriptor 2
CID Descriptor 1
b7 b6 b5 b4 b3
UUI27 UUI26
UUI19 UUI18
UUI25
UUI17
b2
b1
UUI24
UUI16
Data Sheet
b0