DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
8. DS0 MONITORING FUNCTION
Each framer in the DS21354/DS21554 can monitor one DS0 (64kbps) channel in the transmit direction
and one DS0 channel in the receive direction at the same time. In the transmit direction, the user
determines which channel is to be monitored by properly setting the TCM0 to TCM4 bits in the CCR4
register. In the receive direction, the RCM0 to RCM4 bits in the CCR5 register need to be properly set.
The DS0 channel pointed to by the TCM0 to TCM4 bits appears in the transmit DS0 monitor (TDS0M)
register, and the DS0 channel pointed to by the RCM0 to RCM4 bits appears in the receive DS0
(RDS0M) register. The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the
decimal decode of the appropriate E1 channel.
For example, if DS0 channel 6 in the transmit direction and DS0 channel 15 in the receive direction need
to be monitored, then the following values would be programmed into CCR5 and CCR6:
TCM4 = 0
TCM3 = 0
TCM2 = 1
TCM1 = 0
TCM0 = 1
RCM4 = 0
RCM3 = 1
RCM2 = 1
RCM1 = 1
RCM0 = 0
CCR4: COMMON CONTROL REGISTER 4 (Address = A8 Hex)
[Repeated here from Section 5 for convenience.]
(MSB)
(LSB)
RLB
LLB
LIAIS
TCM4
TCM3
TCM2
TCM1
TCM0
SYMBOL POSITION
NAME AND DESCRIPTION
RLB
LLB
CCR4.7
CCR4.6
CCR4.5
Remote Loopback.
Local Loopback.
LIAIS
Line Interface AIS Generation Enable.
Transmit Channel Monitor Bit 4. MSB of a channel decode that
determines which transmit channel data will appear in the TDS0M
register. See Section 8 for details.
TCM4
CCR4.4
TCM3
TCM2
TCM1
TCM0
CCR4.3
CCR4.2
CCR4.1
CCR4.0
Transmit Channel Monitor Bit 3.
Transmit Channel Monitor Bit 2.
Transmit Channel Monitor Bit 1.
Transmit Channel Monitor Bit 0. LSB of the channel decode.
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