DS2154
RCR1: RECEIVE CONTROL REGISTER 1 (Address = 10 Hex)
(MSB)
(LSB)
RESYNC
RSMF
RSM
RSIO
—
—
FRC
SYNCE
SYMBOL
POSITION
NAME AND DESCRIPTION
RSMF
RCR1.7
RSYNC Multiframe Function. Only used if the RSYNC pin is
programmed in the multiframe mode (RCR1.6 = 1).
0 = RSYNC outputs CAS multiframe boundaries
1 = RSYNC outputs CRC4 multiframe boundaries
RSM
RSIO
RCR1.6
RCR1.5
RSYNC Mode Select.
0 = frame mode (see the timing in Section 14)
1 = multiframe mode (see the timing in Section 14)
RSYNC I/O Select. (Note: This bit must be set to 0 when
RCR2.1 = 0.)
0 = RSYNC is an output (depends on RCR1.6)
1 = RSYNC is an input (only valid if elastic store enabled)
—
RCR1.4,
RCR1.3
RCR1.2
Not Assigned. Should be set to 0 when written.
FRC
Frame Resync Criteria.
0 = resync if FAS received in error three consecutive times
1 =resync if FAS or bit 2 of non-FAS is received in error three
consecutive times
SYNCE
RCR1.1
RCR1.0
Sync Enable.
0 = auto resync enabled
1 = auto resync disabled
RESYNC
Resync. When toggled from low to high, a resync is initiated.
Must be cleared and set again for a subsequent resync.
Table 4-1. Sync/Resync Criteria
FRAME OR
MULTIFRAME
LEVEL
SYNC CRITERIA
RESYNC CRITERIA
ITU SPEC.
FAS present in frame N and N + 2, and Three consecutive incorrect
FAS not present in frame N + 1
FAS received
G.706
4.1.1
4.1.2
Alternate (RCR1.2 = 1) the
above criteria is met or three
consecutive incorrect bit 2 of
non-FAS received
FAS
Two valid MF alignment words found
within 8ms
915 or more CRC4 code
words out of 1000 received in
error
Two consecutive MF
alignment words received in
error
G.706
CRC4
CAS
4.2 and 4.3.2
Valid MF alignment word found and
previous time slot 16 contains code
other than all 0s
G.732
5.2
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ROCHESTER [ Rochester Electronics ]
