Datasheet

DS21352/DS21552
54 of 137
9. DS0 MONITORING FUNCTION
The device has the ability to 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 will determine which
channel is to be monitored by properly setting the TCM0 to TCM4 bits in the CCR5 register. In the
receive direction, the RCM0 to RCM4 bits in the CCR6 register need to be properly set. The DS0 channel
pointed to by the TCM0 to TCM4 bits will appear in the Transmit DS0 Monitor (TDS0M) register and
the DS0 channel pointed to by the RCM0 to RCM4 bits will appear 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 T1 channel. For example, if DS0 channel 6 in the transmit direction and DS0 channel
15 in the receive direction needed to be monitored, then the following values would be programmed into
CCR5 and CCR6:
TCM4 = 0 RCM4 = 0
TCM3 = 0 RCM3 = 1
TCM2 = 1 RCM2 = 1
TCM1 = 0 RCM1 = 1
TCM0 = 1 RCM0 = 0
CCR5: COMMON CONTROL REGISTER 5 (Address=19 Hex)
[repeated here from section 6 for convenience]
(MSB) (LSB)
TJC LLB LIAIS TCM4 TCM3 TCM2 TCM1 TCM0
SYMBOL POSITION NAME AND DESCRIPTION
TJC CCR5.7
Transmit Japanese CRC6 Enable.
LLB CCR5.6 Local Loopback.
LIAIS CCR5.5
Line Interface AIS Generation Enable.
TCM4 CCR5.4 Transmit Channel Monitor Bit 4. MSB of a channel decode that determines which
transmit channel data will appear in the TDS0M register. See Section 0 for details.
TCM3 CCR5.3
Transmit Channel Monitor Bit 3.
TCM2 CCR5.2
Transmit Channel Monitor Bit 2.
TCM1 CCR5.1
Transmit Channel Monitor Bit 1.
TCM0 CCR5.0 Transmit Channel Monitor Bit 0. LSB of the channel decode.