DS21458LDK Maxim Integrated, DS21458LDK Datasheet - Page 80

• Manufacturer Part Number: DS21458LDK
• Description: Network Controller & Processor ICs
• Manufacturer: Maxim Integrated

14. LOOPBACK CONFIGURATIONS
The DS21455/DS21458 have four loopback configurations including Framer, Payload, Local, and
Remote loopback.
Payload loopback may be done on a per-channel basis if both the transmit and receive paths are
synchronous (RCLK = TCLK and RSYNC = TSYNC). See Section 14.1.
Figure 14-1. Normal Signal Flow Diagram
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bit 0/Framer Loopback (FLB).
0 = loopback disabled
1 = loopback enabled
LTS
RECEIVE
7
0
TRANSMIT
RECEIVE
TRANSMIT
LIU
LIU
LIU
LIU
Figure 14-1
—
LBCR
Loopback Control Register
4Ah
6
0
ATTENUATOR
ATTENUATOR
depicts a normal signal flow without any loopbacks enabled
ATTENUATOR
ATTENUATOR
—
5
0
JITTER
JITTER
JITTER
JITTER
FRAMER LOOPBACK
LIUC
NORMAL MODE
4
0
80 of 269
LLB
3
0
RECEIVE
FRAMER
TRANSMIT
RECEIVE
FRAMER
TRANSMIT
FRAMER
DS21455/DS21458 Quad T1/E1/J1 Transceivers
FRAMER
RLB
2
0
PLB
1
0
BACKPLANE
BACKPLANE
BACKPLANE
BACKPLANE
I/F
I/F
I/F
I/F
FLB
0
0
.