PM7344 datasheet(253/293 Pages) PMC

253 / 293 page

PM7344 S/UNI-MPH

DATA SHEET

PMC-950449

ISSUE 6

MULTI-PHY USER NETWORK INTERFACE

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

237

After an abort, the RFDL state machine will be in the receiving all ones state, and

the data link status will be idle. When the first flag is detected, a new interrupt

will be generated, with a dummy data byte loaded into the FIFO buffer, to

indicate that the data link is now active.

Figure 28

- RFDL FIFO Overrun

Serial Data

extracted from

ESF FDL

RDLINT[x]

RDLEOM[x]

D[7:0]

Flag

Dn R C1

C2 Flag D1

B2 B3

STATUSRD

Dn-1

OVR

R Abort

This diagram shows the relationship between RFDL inputs and outputs for the

case where interrupts are programmed to occur when two data bytes are present

in the FIFO buffer. Each read is composed of two register reads, as described

above. In this example, data is not read by the end of B2. An overrun occurs

since unread data (Dn-3) has been overwritten by B1. This sets the RDLEOM[x]

output high, and resets both the RFDL and the FIFO buffer. The RFDL is held

disabled until the Status Register is read. The start flag sequence is not

detected since the RFDL is still held disabled when it occurs. Consequently, the

RFDL will ignore the entire frame including the abort sequence (since it has not

occurred in a valid frame or during flag reception, according to the RFDL).

PM7344 Datasheet(PDF) 253 Page - PMC-Sierra, Inc