MT92220BG Zarlink Semiconductor, MT92220BG Datasheet - Page 117

• Manufacturer Part Number: MT92220BG
• Description: Description = 1023 Channel Voice Over IP/AAL2 Processor ;; Package Type = Epbga ;; No. Of Pins = 608
• Manufacturer: Zarlink Semiconductor

Data Sheet
Treatment of xxPCM channels can produce Event Reports that contain xxPCM-specific errors: Underrun errors,
Underrun 2 errors, Overrun errors, as well as BL2 (Bad Packet Length 2) which means that the number of payload
samples was not divisible by the number of bearers, and the BL3 (Bad Packet Length 3) which means that the
packet was too large to fit in the circular buffer. If any samples were lost, the SL bit will be set, and the number of
lost samples will be reported in the 32-bit Samples Lost field. Initialization of the channel in the RX xxPCM Channel
Structure, or the I2, Initialization in the Common PDV Absorption Structure can also be reported. In addition to
reporting all these errors, the xxPCM report structure gives the base address of the RX xxPCM Channel structure
(to identify the channel to which the report structure belongs), the current Local Bus Timestamp and the current
Remote Timestamp.
The format of the xxPCM Event Report is the following:
U2
U
O
I
I2
Field
Figure 62 - RX Disassembly Event Report Queue - xxPCM Channel Report
+A
+C
+E
+0
+2
+4
+6
+8
b15
U2
b14
U
b13
Underrun Detected 2. This bit is set when a packet is received with a remote
time stamp that would require the first sample of the packet to be output on the
TDM bus one or many frames ago. This means that the received packet was
late as compared to its expected arrival time.
Underrun Detected. This bit is set when a packet is received with a remote time
stamp that would require the first sample of the packet to be output on the TDM
bus one or many frames ago after the worst expected packetization delay was
added to the arrival time. For example, if a 44 sample PCM packet is
processed by a structure that expects 88 samples as the maximum packet
size, it may only be output on the TDM bus in 44 frames; a received time stamp
that would contradict this requirement would cause an underrun slip.
timestamp and number of samples that require the last sample of the packet to
be sent out on the TDM bus with a delay greater that the Maximum Used
Samples in Circular Buffer.
When set, a packet has been received for the first time by the RX xxPCM
Channel Structure.
When set, a packet has been received for the first time by the Common PDV
Absorption structure.
Overrun Detected. This bit is set when a packet is received with a remote
O
b12
I
RX xxPCM Channel Structure Address [20:5]
Table 47 - Fields and Description
b11
I2
RPM
Local Bus Time Stamp [31:16]
b10
Local Bus Time Stamp [15:0]
Remote Time Stamp [31:16]
Zarlink Semiconductor Inc.
Remote Time Stamp [15:0]
Samples Lost [31:16]
Samples Lost [15:0]
RSx
b9
SL
b8
BL2
b7
PLX
b6
Description
BL4
b5
BL3
b4
XD
b3
b2
b1
b0
0
MT92220
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