ds2156gn Maxim Integrated Products, Inc., ds2156gn Datasheet - Page 88

• Manufacturer Part Number: ds2156gn
• Description: Ds2156, Ds2156l, Ds2156ln T1/e1/j1 Single-chip Transceiver Tdm/utopia Ii Interface
• Manufacturer: Maxim Integrated Products, Inc.

14.
The DS2156 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 determines which
channel is to be monitored by properly setting the TCM0 to TCM4 bits in the TDS0SEL register. In the
receive direction, the RCM0 to RCM4 bits in the RDS0SEL register need to be properly set. The DS0
channel pointed to by the TCM0 to TCM4 bits appear in the transmit DS0 monitor (TDS0M) register.
The DS0 channel pointed to by the RCM0 to RCM4 bits 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 T1or E1 channel. T1 channels 1 through 24 map to register values 0 through 23. E1 channels
1 through 32 map to register values 0 through 31. 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 TDS0SEL and RDS0SEL:
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bits 0 to 4/Transmit Channel Monitor Bits (TCM0 to TCM4). TCM0 is the LSB of a 5-bit channel select that
determines which transmit channel data appear in the TDS0M register.
Bits 5 to 7/Unused, must be set to 0 for proper operation
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bits 0 to 7/Transmit DS0 Channel Bits (B1 to B8). Transmit channel data that has been selected by the transmit
channel monitor select register. B8 is the LSB of the DS0 channel (last bit to be transmitted).
DS0 MONITORING FUNCTION
B1
—
7
7
0
0
B2
—
TDS0SEL
Transmit Channel Monitor Select
74h
TDS0M
Transmit DS0 Monitor Register
75h
6
0
6
0
B3
—
5
0
5
0
TCM4 = 0
TCM3 = 0
TCM2 = 1
TCM1 = 0
TCM0 = 1
TCM4
B4
4
0
4
0
88 of 265
TCM3
B5
3
0
3
0
RCM4 = 0
RCM3 = 1
RCM2 = 1
RCM1 = 1
RCM0 = 0
TCM2
B6
2
0
2
0
TCM1
B7
1
0
1
0
TCM0
B8
0
0
0
0