PM7323 Datasheet, PDF (195/219 Pages) PMC-Sierra, Inc – ROUTING CONTROL, MONITORING, & POLICING 200 MBPS

STANDARD PRODUCT
PM7323 RCMP-200
DATASHEET
PMC-960543
ISSUE 2
ROUTING CONTROL, MONITORING, & POLICING
200 MBPS
Figure 19 - Input Cell Interface Address Line Polling Master
Configuration (IPOLL=1) – Example 2
IFCLK (I)
ICA[1] (I)
CA(N+7)
CA(N+8)
CA(N+9)
CA(N+8)
CA(N+9)
IWRENB[1] (O)
IADDR[4:0] (O) _{N+7 1Fh N+8 1Fh N+9 1Fh}
N+8
1Fh N+9 1Fh N+10
IAVALID (O)
ISOC (I)
IDAT[7:0] (I) _W(n-2) _W(n-1) _W(n) _{XX XX XX XX XX XX XX W1 W2 W3}
IPRTY (I)
Figure 18 and Figure 19 illustrate the operation of the Input Cell Interface when it
arbitrates accesses for up to 32 PHYs using address line polling. The ICA[1] and
IWRENB[1] control signals are active.
The PHY devices are polled cyclically beginning with PHY#(N+1) where N is the
PHY ID of the cell currently being transferred. The first PHY device to respond to
polling with an available cell indication is selected for transfer of the next cell. If
no PHY device responds with an available cell indication, the polling cycle
repeats. If the polling cycle repeats while the current cell is being transferred,
however, the PHY ID of the cell being transferred (i.e. N) is omitted from the
polling sequence. This is because PHY devices compliant with the UTOPIA
Level 1 interface (which can be used in polling mode with external glue logic)
cannot indicate availability of a subsequent cell while they are simultaneously
transferring a cell. Once transfer of the current cell is complete, PHY#N is re-
inserted into the polling sequence.
Proprietary and Confidential to PMC-Sierra, Inc.
184
and for its Customer’s Internal Use.