DS2154
CCR5: COMMON CONTROL REGISTER 5 (Address = AA Hex)
(MSB)
(LSB)
RCM0
LIRST
—
—
RCM4
RCM3
RCM2
RCM1
SYMBOL
POSITION
NAME AND DESCRIPTION
LIRST
CCR5.7
Line Interface Reset. Setting this bit from a 0 to a 1 will initiate
an internal reset that affects the clock recovery state machine and
jitter attenuator. Normally this bit is only toggled on power-up.
Must be cleared and set again for a subsequent reset.
—
CCR5.6,
CCR5.5
CCR5.4
Not Assigned. Should be set to 0 when written.
RCM4
Receive Channel Monitor Bit 4. MSB of a channel decode that
determines which receive channel data will appear in the
RDS0M register. See Section 7 for details.
RCM3
RCM2
RCM1
RCM0
CCR5.3
CCR5.2
CCR5.1
CCR5.0
Receive Channel Monitor Bit 3.
Receive Channel Monitor Bit 2.
Receive Channel Monitor Bit 1.
Receive Channel Monitor Bit 0. LSB of the channel decode.
4.1 Framer Loopback
When CCR1.7 is set to 1, the DS2154 enters a Framer Loopback (FLB) mode. See Figure 1-1 for details.
This loopback is useful in testing and debugging applications. In FLB, the DS2154 loops data from the
transmit side back to the receive side. When FLB is enabled, the following occurs:
1) Data is transmitted as normal at TPOSO and TNEGO.
2) Data input via RPOSI and RNEGI is ignored.
3) The RCLK output is replaced with the TCLK input.
4.2 Local Loopback
When CCR4.6 is set to 1, the DS2154 is forced into Local Loopback (LLB). In this loopback, data
continues to be transmitted as normal through the transmit side of the DS2154. Data being received at
RTIP and RRING is replaced with the data being transmitted. Data in this loopback passes through the
jitter attenuator. See Figure 1-1 for more details.
4.3 Remote Loopback
When CCR4.7 is set to 1, the DS2154 is forced into Remote Loopback (RLB). In this loopback, data
input via the RPOSI and RNEGI pins is transmitted back to the TPOSO and TNEGO pins. Data continues
to pass through the receive side framer of the DS2154 as it would normally, and the data from the
transmit side formatter is ignored. See Figure 1-1 for more details.
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ROCHESTER [ Rochester Electronics ]
