mt90502ag2 Zarlink Semiconductor, mt90502ag2 Datasheet - Page 52

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

2.4.1
For each VC directed to the RX SAR, an RX AAL2 VC structure exists in external memory. The RX AAL2 VC
structures contain the following:
•
•
•
When a VC is opened, the lost bit must be set, the error report enable bit must be set (if per-VC errors are to be
reported) or reset (if no per-VC errors are to be reported), and the received cell counter must be initialized to 0.
+1FE80h
+1FF00h
+1FF80h
The RX AAL2 VC structures are fixed structures
located at the beginning of RX SSRAM memory
through 0 to addresses +3F80h, +7F80h,
+FF80h and +1FF80h for 128, 256, 512 and
1023 channels respectively.
Each structure is 128 bytes in size.
Fields in Italic are used by hardware only. Fields in Plain are written to by the CPU/Software.
LI:
LST:
SN:
Straddle Offset:
ER:
Received Cell Counter: Free running counter of the number of cells received by this VC so far.
information required to detect errors
a free-running received cell counter
bytes received of from a CPS-Packet that is straddling the current and next AAL2 cells.
+100h
+00h
+80h
RX AAL2 VC Structure
VC Number 1021
VC Number 1022
VC Number 1023
VC Number 0
VC Number 1
VC Number 2
Length of the packet currently in transition.
Lost Bit. Indicates that the RX SAR detected an error in the last cell it received. Must be set to “1” at start-up.
Expected Sequence Number of next cell.
The number of bytes that have been received so far in the transitioning packet.
Error Report Enable. When “1’, the RX SAR will report cell-level errors, Sequence Number errors, Offset,
Parity, and AAL2 HEC errors.
Figure 22 - RX AAL2 VC Structure
+10h
+12h
+14h
+16h
+50h
+52h
+Ah
+Ch
+Eh
RX AAL2 VC Structure
+0h
+2h ER
+4h
+6h
+8h
Zarlink Semiconductor Inc.
b15 b14 b13 b12 b11 b10 b9 b8
MT90502
UUI[2:0]
52
CPS-Payload 59
CPS-Payload 61
CPS-Payload 1
CPS-Payload 3
CID [7:0]
LI[5:0]
Received Cell Counter [31;16]
Received Cell Counter [15:0]
HEC
LST SN
b7 b6 b5 b4 b3
LI [5:0]
CPS-Payload 60
CPS-Payload 62
CPS-Payload 0
CPS-Payload 2
CPS-Payload 4
Straddle Offset [6:0]
Data Sheet
b2
Reserved
UUI [4:3]
b1
b0