MT92220BG Zarlink Semiconductor, MT92220BG Datasheet - Page 70

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

70
8.2
When events indicating the assembly of RTP or AAL2 packets are read and treated by the service timer, they are
written into a packet assembly queue to be treated in order. HDLC CPS-packets that complete also generate
events in this packet assembly queue independently of the service timer.
The CPU can also generate packets to be inserted in an active connection. To do so, it writes the packets' payload
in external memory (including the RTP header if any, or the HDLC control byte containing the UUI in AAL2), and
writes a descriptor to registers. This descriptor is then inserted into the event queue and treated by the chip. By
inserting packets into an active connection instead of constructing the packets entirely itself, it allows the chip to
manage the consistency of the RTP header across packets. For example, the sequence number will be incremental
across all packets on an IP/RTP connection, not just on voice packets generated by the chip.
SS:
ST:
Serv Timer #
Tx Connection
Structure Base [20:6]
Field
Event Queue
each TX AAL2 VC Structure and determine if they are due to be sent because one of
the packets in the partially filled cell’s CPS timer expired.
Service Timer number
Base address of Tx AAL2 or RTP Connection Structure to which this event is being
sent. The base address is pointed to in increments of 64 bytes.
Start scanning bit. When set, this field tells the TX AAL2 VC Scanning Process to read
Start Channel. A channel will only power-up on an event that has this bit set to ‘1’.
+(N-3)*10h
+(N-2)*10h
+(N-1)*10h
+10
+20
Figure 36 - Assembly Event Queue
+0
N = {1024, 2048, 4096}
Start/Cross Boundary = {16K, 32K, 64K} bytes
Zarlink Semiconductor Inc.
Assembly Event N-3
Assembly Event N-2
Assembly Event N-1
Assembly Event 0
Assembly Event 2
Assembly Event 1
Description