DS3172 Maxim Integrated, DS3172 Datasheet - Page 49

• Manufacturer Part Number: DS3172
• Description: Network Controller & Processor ICs Dual DS3/E3 Single Chip Transceiver
• Manufacturer: Maxim Integrated

Specifications of DS3172

• Part # Aliases: 90-31720-000

Table 9-1. Configuration of Port Register Settings
Note: The Line Mode has been configured with the LIU enabled and the JA in the receive path (LM[2:0] = 011) for
all modes. Only Port 1 registers have been displayed.
Test the DS317x with the following configuration settings.
MODE
DS3 C-Bit SCT
DS3 M13 SCT
E3.751 SCT
E3.823 SCT
Considerations
For best performance of the CLAD to meet jitter requirements across the temperature range, especially @ -40 C,
the following test registers should be set after reset:
Address 0x20B = 0x11
Address 0x20F = 0x11
9.1 Monitoring and Debugging
To determine if the device is receiving a good signal and that the chip is correctly configured for its environment,
check the following status registers.
Receive Loss of Lock – PORT.SR.RLOL – The clock recovery circuit of the LIU was unable to recover the clock
from the incoming signal. This may indicate that the LIU’s master clock does not match the frequency of the
incoming signal. Verify that the CLAD is configured to match the clock input on the CLKA, CLKB, and CLKC pins
(DS3, E3, STS-1). See
Loss of Signal – LINE.RSR.LOS – This indicates that the LIU is unable to recover the clock and data because
there is no signal on the line, or that the signal is attenuated beyond recovery.
Loss of Frame – T3.RSR1.LOF (or E3751.RSR1 or E3832.RSR1) – This indicates that the framer was unable to
synchronize to the incoming data. Verify that the FM bits have been correctly configured for the correct mode of
traffic (DS3, E3 G.751, E3 G.832)
Other helpful techniques to utilize in diagnosing a problem include using Line Loopback and Diagnostic Loopback.
These features help to isolate and identify the source of the problem. Line Loopback will loop the receive input to
the transmit output, eliminating the transmit side input from the equation. Diagnostic Loopback will loop the transmit
output before the LIU to the receive framer, eliminating the analog Receive LIU and the receive side analog
circuitry.
One other potential problem is the Line Encoding/Decoding. The device needs to be configured in the same
mode as the far end piece of equipment. If the far end piece of equipment is transmitting and receiving HDB3/B3ZS
encoded data, the DS317x also must be configured to do the same. This is controlled by the LINE.TCR.TZSD and
the LINE.RCR.RZSD bits.
Table
10-11.
PORT.CR1
0x040
0x7C00
0x7C00
0x7C00
0x7C00
PORT.CR2
0x042
0000 0011 0000 0111
0000 0011 0000 1111
0000 0011 0001 0111
0000 0011 0001 111X
49
PORT.CR3
0x044
0x0000
0x0000
0x0000
0x0000
PORT.CR4
0x046
0x0000
0x0000
0x0000
0x0000