MT8971B データシートの表示（PDF） - Mitel Networks
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MT8971B Datasheet PDF : 20 Pages
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MT8971B/72B
C-Channel Internal Control Internal Diagnostic
(Bit 0-7)
Register
Register
Description
XXX01111
00000000
XXX11111
00010000
01000000
01000000
Default Mode-1: Bit rate is 80 kbit/s. ATTACK,
PSEN, DINB, DRR and all diagnostics are disabled.
TxHK=0.
Default Mode-2 Bit rate is 160 kbit/s. ATTACK,
PSEN, DINB, DRR and all diagnostics are disabled.
TxHK=0.
Table 4a. Default Mode Selection
Notes:
Default Mode 1 can also be selected by tying CDSTi/CDi pin low when DNIC is operating in dual mode.
Default Mode 2 can also be selected by tying CDSTi/CDi pin high when DNIC is operating in dual mode.
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
Reg Sel-1 Reg Sel-2
Loopback
FUN
PSWAP
DLO
Default Mode Selection
(Refer to Table 4a)
Not Used
Bit
Name
Description
0
Reg Sel-1
Register Select-1. Must be set to ’0’ to select the Diagnostic Register.
1
Reg Sel-2
Register Select-2. Must be set to ’1’ to select the Diagnostic Register.
2,3
Loopback
Bit 2 Bit 3
0 0 All loopback testing functions disabled. Normal operation.
0 1 DSTi internally looped back into DSTo for system diagnostics.
1
1
0
1
LOUT is internally looped back into LIN for
DSTo is internally looped back into DSTi
system diagnostics.
for end-to-end testing.
4
FUN
Force Unsync. When set to ’1’, the DNIC is forced out-of-sync to test the SYNC
recovery circuitry. When set to ’0’, the operation continues in synchronization.
5
PSWAP
Polynomial Swap. When set to ’1’, the scrambling and descrambling polynomials
are interchanged (use for MAS mode only). When set to ’0’, the polynomials retain
their normal designations.
6
DLO
Disable Line Out. When set to ’1’, the signal on LOUT is set set to VBias. When set to
’0’, LOUT pin functions normally.
7
Not Used
Must be set to ’0’ for normal operation.
Table 5. Diagnostic Register
Notes:
When bits 4-7 of the Diagnostic Register are all set to one, the DNIC operates in one of the default modes as defined in Table 4a,
depending upon the status of bit-3.
Do not use LOUT to LIN loopback in DN/SLV mode.
Do not use DSTo to DSTi loopback in MOD/MAS mode.
and CLD with TCK defining the bits and CLD the
channel boundaries of the data stream as shown in
Figure 8.
Line Port (LIN, LOUT)
The line interface is made up of LOUT and LIN with
LOUT driving the transmit signal onto the line and LIN
receiving the composite transmit and receive signal
from the line. The line code used in the DNIC is
Biphase and is shown in Figure 10. The scrambled
NRZ data is differentially encoded meaning the
previous differential encoded output is XOR’d with
the current data bit which produces the current
output. This is then biphase encoded where
transitions occur midway through the bit cell with a
negative going transition indicating a logic "0" and a
positive going transition indicating a logic "1".
9-117
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