Rainbow Electronics DS3170 - Manual (Page 52)

DS3170 DS3/E3 Single-Chip Transceiver
52 of 233
Table 8-1. Configuration of Port Register Settings
MODE
PORT.CR1
0x040
PORT.CR2
0x042
PORT.CR3
0x044
PORT.CR4
0x046
DS3 C-Bit Framed 0x2000 0000 0011 0000 0111 0x0000 0x0000
DS3 M13 Framed 0x2000 0000 0011 0000 1111 0x0000 0x0000
E3.751 Framed 0x2000 0000 0011 0001 0111 0x0000 0x0000
E3.823 Framed 0x2000 0000 0011 0001 111X 0x0000 0x0000
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.
8.1 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 REFCLK pin (DS3, E3, STS-1).
See
Table 9-11 .
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 DS3170 also must be configured to do the same. This is controlled by the LINE.TCR.TZSD and
the LINE.RCR.RZSD bits.