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STANDARD PRODUCT
PMC-Sierra, Inc.
PM6344 EQUAD
PMC-951013
ISSUE 5
QUADRUPLE E1 FRAMER
195
b) If FLG=0 (i.e. an abort has been received) and the link state was active,
then set the link state to inactive, discard the current frame, and go to step 1.
c) If FLG=1 and the link state was inactive, then set the link state to active,
discard the last data byte, and go to step 1.
ELSE
d) Save the last data byte read.
e) If EOM=1, then read the CRC and NVB[2:0] bits of the RFDL Status
Register to process the frame properly.
f) If FE=0, then go to step 2, else go to step 1.
The link state is typically a local software variable. The link state is inactive if the
RFDL is receiving all ones or receiving bit-oriented codes which contain a
sequence of eight ones. The link state is active if the RFDL is receiving flags or
data.
Interrupt Mode
In the interrupt driven mode, the processor controlling the RFDL uses either the
RDLINT[x] output, or the main processor INTB output (RDLINTE bit of the
Datalink Options Register is set to logic 1), the Interrupt ID/Clock Monitor, and
the Interrupt Source Registers, to determine when to read the Data Register.
The RXDMASIG bit in the Datalink Options Register should be set to logic 1.
RDLINTE of the same register should be set to logic 1 if the INTB output is used
as the interrupt source. The processor interrupt service routine should process
the data in the following order:
1. Wait for an interrupt originating from the RFDL. Once the interrupt is set, then
proceed to step 2.
2. Read the RFDL Data Register.
3. Read the RFDL Status Register to check for the following:
a) If OVR=1, then discard the current frame and go to step 1.
ELSE
b) If FLG=0 (i.e. an abort has been received) and the link state was active,
then set the link state to inactive, discard the current frame, and go to step 1.