Ds0 monitoring function, 1 transmit ds0 monitor registers – Maxim Integrated DS21Q55 User Manual
Page 79
Product Preview
DS21Q55
79 of 248
012103
Please contact
or search
http://www.maxim-ic.com
for updated
information.
14. DS0 MONITORING FUNCTION
The DS21Q55 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 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 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 or 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:
TCM4 = 0
RCM4 = 0
TCM3 = 0
RCM3 = 1
TCM2 = 1
RCM2 = 1
TCM1 = 0
RCM1 = 1
TCM0 = 1
RCM0 = 0
14.1 Transmit DS0 Monitor Registers
Register Name:
TDS0SEL
Register Description:
Transmit Channel Monitor Select
Register Address:
74h
Bit #
7
6
5
4
3
2
1
0
Name
-
-
-
TCM4
TCM3
TCM2
TCM1
TCM0
Default
0
0
0
0
0
0
0
0
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 will appear in the TDS0M register.
Bits 5 to 7/Unused, must be set to zero for proper operation.
Register Name:
TDS0M
Register Description:
Transmit DS0 Monitor Register
Register Address:
75h
Bit #
7
6
5
4
3
2
1
0
Name
B1
B2
B3
B4
B5
B6
B7
B8
Default
0
0
0
0
0
0
0
0
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).