CN8236EBGB Mindspeed Technologies, CN8236EBGB Datasheet - Page 146

• Manufacturer Part Number: CN8236EBGB
• Description: ATM SAR 155Mbps 3.3V ABR/CBR/GFR/UBR/VBR 388-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8236EBGB

• Package: 388BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 155 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V

5.0 Reassembly Coprocessor
5.6 Status Queue Operation
5.6.2 Status Queue Overflow or Full Condition
5-36
A status queue overflow or full condition is entered when the last available status
queue entry is written. The reassembly coprocessor detects the condition by
comparing the WRITE+1 and READ_UD index pointers. If the pointers are
equal, a status overflow condition is detected and the RSM coprocessor sets the
internal OVFL bit in the last status queue entry written to a logic high, to indicate
the condition. The RSM coprocessor also sets to one either the RSM_HS_FULL
bit in the HOST_ISTAT1 register, or the RSM_LS_FULL bit in the LP_ISTAT1
register, to prompt an interrupt.
cells. If a COM or EOM cell is received while the status queue is full, the channel
is marked for status-full packet discard. Once an SSM, EOM, or OAM cell is
received during a status-full condition, the cell is discarded and the status queue
checked. If there is now room in the status queue, the status-full condition is
exited.
to detect the full condition and advise the peers to check if their queues have
overflowed. Each peer would then check the OVFL bit in the last status queue
entry written (pointed to by READ_UD – 1), to determine if that peer’s status
queue has filled. If the OVFL bit is not set to a logic high, the host should also
check the entry pointed to by (READ_UD2 – 1) to determine if an overflow
condition occurred during a host update of the READ_UD index pointer. Because
the reassembly coprocessor recovers from the overflow condition automatically,
the host does not have to determine which queue overflowed.
performs EPD on channels marked for packet discard due to the status overflow
condition, when a cell is received on any of those channels. Cells up to and
including the next EOM are discarded. Status queue overflow protection can be
globally disabled by setting RSM_CTRL0(RSM_STAT_DIS) to a logic high.
NOTE:
While the reassembly coprocessor is in status-full condition, it discards all
For multiple peer configurations, the user can configure an interrupt manager
After a status group has exited a full condition, the RSM coprocessor
Avoid having the Status Queue Overflow (or Full Condition) and DMA
FIFO Buffer Full conditions at the same time.
Mindspeed Technologies
ATM ServiceSAR Plus with xBR Traffic Management
™
28236-DSH-001-B
CN8236