
DS3161/DS3162/DS3163/DS3164
Bit 4: Loop Time Enable (LOOPT). When this bit is set, the port is in loop time mode. The transmit clock is set to
the receive clock from the RLCLKn pin or the recovered clock from the CLAD clock and the TCLKIn pin is not used.
This function of this bit is conditional on other control bits. See
Table 10-3 for more details.
0 = Normal transmit clock operation
1 = Transmit using the receive clock
Bit 3: CLAD Transmit Clock Source Control (CLADC). This bit is used to enable the CLAD clocks as the
source of the internal transmit clock. This function of this bit is conditional on other control bits. See
Table 10-3 for
more details.
0 = Use CLAD clocks for the transmit clock as appropriate
1 = Do not use CLAD clocks for the transmit clock – (if no loopback is enabled, TCLKIn is the source)
Bit 2: Receive Framer IO Signal Timing Select (RFTS). This bit controls the timing reference for the signals on
the receive framer interface IO pins. The pins controlled are RSERn, RSOFOn / RDENn / RFOHENn and
0 = Use output clocks for timing reference
1 = Use input clocks for timing reference
Bit 1: Transmit Framer IO Signal Timing Select (TFTS). This bit controls the timing reference for the signals on
the transmit framer interface IO pins. The pins controlled are TOHMIn / TSOFIn, TFOHn / TSERn, TFOHENIn and
TSOFOn / TDENn / TFOHENOn. See
Table 10-6 for more details.
0 = Use output clocks for timing reference
1 = Use input clocks for timing reference
Bit 0: Transmit Line IO Signal Timing Select (TLTS). This bit controls the timing reference for the signals on the
transmit line interface IO pins. The pins controlled are TPOSn / TDATn and TNEGn / TOHMOn. See
Table 10-5 for
more details.
0 = Use output clocks for timing reference
1 = Use input clocks for timing reference
Register Name:
PORT.CR4
Register Description:
Port Control Register 4
Register Address:
(0,2,4,6)46h
Bit #
15
14
13
12
11
10
9
8
Name
--
SLB
LBM2
LBM1
LBM0
Default
0
Bit #
7
6
5
4
3
2
1
0
Name
GPIOB3
GPIOB2
GPIOB1
GPIOB0
GPIOA3
GPIOA2
GPIOA1
GPIOA0
Default
0
Bit 11: System Bus Loopback (SLB). This bit enables the system bus loopback mode per port when the bit is
set. ATM cells and/or HDLC packets are looped back from the transmit system bus to the receive system bus
through the FIFOs. See
Figure 10-9 for the block diagram highlighting loopback features.
Bits 10 to 8: Loopback Mode [2:0] (LBM[2:0]). These bits select the loopback modes for analog loopback (ALB),
line loopback (LLB), payload loopback (PLB) and diagnostic loopback (DLB). See
Table 10-15 for the loopback
select codes. Default: No Loopback.
110
0
1
0
1