DS2151 Dallas Semiconducotr, DS2151 Datasheet - Page 12

• Manufacturer Part Number: DS2151
• Description: T1 Single-Chip Transceiver
• Manufacturer: Dallas Semiconducotr

CCR1: COMMON CONTROL REGISTER 1 (Address=37 Hex)
LOCAL LOOPBACK
When CCR1.6 is set to a 1, the DS2151Q will be forced into Local LoopBack (LLB). In this loopback,
data will continue to be transmitted as normal through the transmit side of the SCT. Data being received
at RTIP and RRING will be replaced with the data being transmitted. Data in this loopback will pass
through the jitter attenuator and the jitter attenuator should be programmed to be in the transmit path.
LLB is primarily used in debug and test applications. Please see the DS2151Q Block Diagram in Section
1 for more details.
REMOTE LOOPBACK
When CCR1.4 is set to a 1, the DS2151Q will be forced into Remote LoopBack (RLB). In this loopback,
data recovered off the T1 line from the RTIP and RRING pins will be transmitted back onto the T1 line
(MSB)
TESE
SYMBOL POSITION NAME AND DESCRIPTION
SCLKM
RSAO
RESE
TESE
LLB
RLB
LLB
PLB
FLB
CCR1.7
CCR1.6
CCR1.5
CCR1.4
CCR1.3
CCR1.2
CCR1.1
CCR1.0
RSAO
Transmit Elastic Store Enable.
0=elastic store is bypassed
1=elastic store is enabled
Local Loopback.
0=loopback disabled
1=loopback enabled
Receive Signaling All 1s.
0=allow robbed signaling bits to appear at RSER
1=force all robbed signaling bits at RSER to 1
Remote Loopback.
0=loopback disabled
1=loopback enabled
SYSCLK Mode Select.
0=if SYSCLK is 1.544 MHz
1=if SYSCLK is 2.048 MHz
Receive Elastic Store Enable.
0=elastic store is bypassed
1=elastic store is enabled
Payload Loopback.
0=loopback disabled
1=loopback enabled
Framer Loopback.
0=loopback disabled
1=loopback enabled
RLB
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SCLKM
RESE
PLB
DS2151Q
(LSB)
FLB