PM6341 E1XC
DATA SHEET
PMC-910419
ISSUE 8
E1 FRAMER/TRANSCEIVER
14.4.1 Payload Loopback
When PAYLOAD loopback (PAYLB) is initiated by writing 20H to the Master
Diagnostics Register, the E1XC is configured to internally connect the output of
the ELST to the PCM input of TRAN.The data is read out of ELST timed to the
transmitter clock, and the transmit frame alignment indication is used to
synchronize the output frame alignment of ELST. Note, that the BTSIG stream is
still presented to the TRAN; therefore, the SIGEN and DLEN bits of the TRAN
Configuration register should be cleared to logic 0 if the signalling is to be looped
back. Conceptually, the data flow through E1XC in this loopback condition can
be shown as follows:
Figure 27
- Payload Loopback
BTSIG
BTPCM
BTCLK
BTFP
XPLS
DJAT
TRAN
BRFPI
BRCLK
BRPCM
ELST
AIS
RSLC
CDRC
FRMR
14.4.2 Line Loopback
When LINE loopback (LINELB) is initiated by writing 10H to the Master
Diagnostics Register, the E1XC is configured to internally connect the dual-rail
positive and negative line data pulses output from CDRC to the dual-rail inputs of
DJAT. If either the transmit or receive is in unipolar mode, the appropriate line
decoding or encoding is performed. Conceptually, the data flow through E1XC in
this loopback condition can be shown as follows:
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PMC [ PMC-SIERRA, INC ]
