Rainbow Electronics DS2180A User Manual
Page 14
DS2180A
041995 14/36
RECEIVE CONTROL REGISTER Figure 12
(MSB)
(LSB)
ARC
OOF
RCI
RCS
SYNCC
SYNCT
SYNCE
RESYNC
SYMBOL
POSITION
NAME AND DESCRIPTION
ARC
RCR.7
Auto Resync Criteria.
0 = Resync on OOF or RCL event.
1 = Resync on OOF only.
OOF
RCR.6
Out-of-frame (OOF) Condition Detection.
0 = 2 of 4 framing bits in error.
1 = 2 of 5 framing bits in error.
RCI
RCR.5
Receive Code Insert. When set, the receive code selected by RCR.4 is
inserted into channels marked by RMR registers. If clear, no code is in-
serted.
RCS
RCR.4
Receive Code Select.
0 = Idle code (7F Hex).
1 = Digital milliwatt.
SYNCC
RCR.3
Sync Criteria. Determines the type of algorithm utilized by the receive syn-
chronizer and differs for each frame mode.
193S Framing (CCR.4=0).
0 = Synchronize to frame boundaries using F
T
pattern, then search for mul-
tiframe by using F
S
.
1 = Cross couple F
T
and F
S
patterns in sync algorithm.
193E Framing (CCR.4=1).
0 = Normal sync (utilizes FPS only).
1 = Validate new alignment with CRC before declaring sync.
SYNCT
RCR.2
Sync Time. If set, 24 consecutive F-bits of the framing pattern must be
qualified before sync is declared. If clear, 10 bits are qualified.
SYNCE
RCR.1
Sync Enable. If clear, the transceiver will automatically begin a resync if
two of the previous four or five framing bits were in error or if carrier loss is
detected. If set, no auto resync occurs.
RESYNC
RCR.0
Resync. When toggled low to high, the transceiver will initiate resync im-
mediately. The bit must be cleared, then set again for subsequent resyncs.
RECEIVE CODE INSERTION
Incoming receive channels can be replaced with idle (7F
Hex) or digital milliwatt (
µ
-LAW format) codes. The re-
ceive mark registers indicate which channels are in-
serted. When set, bit RCR.5 serves as a “global” enable
for marked channels and bit RCR.4 selects inserted
code format: 0 = idle code, 1 = digital milliwatt.
RECEIVE SYNCHRONIZER
Bits RCR.0 through RCR.3 allow the user to control op-
erational characteristics of the synchronizer. Sync algo-
rithm, candidate qualify testing, auto resync, and com-
mand resync modes may be altered at any time in
response to changing span conditions.