CX28394/28395/28398
3.0 Registers
Quad/x16/Octal—T1/E1/J1 Framers
3.9 Receiver Registers
UP_LEN[1:0]
Loopback Activate Code Length—Selects the number of loopback pattern bits from LBA
[addr 043] that are compared to received data. This is done in order to determine whether a
Loopback Activate Code [LOOPUP; addr 048] has been detected. LOOPUP is recovered if the
received data pattern contains fewer than 63 bit errors in a 24 ms period, or lost if 64 or more
bit errors are detected in a subsequent 24 ms period. F-bits that overwrite or are inserted into
the loopback pattern are not counted as bit errors. Accurate code detection is provided on lines
with up to 1E-3 BER.
UP_LEN
LBA Length
4 bits
00
01
10
11
5 bits
6 bits
7 bits
043—Loopback Activate Code Pattern (LBA)
Unused bits are reserved and should be written to 0.
7
6
5
4
3
2
1
0
LBA[1]
LBA[2]
LBA[3]
LBA[4]
LBA[5]
LBA[6]
LBA[7]
—
LBA[1]
First bit expected of LOOPUP pattern
Second bit expected of LOOPUP pattern
Third bit expected of LOOPUP pattern
LBA[2]
LBA[3]
LBA[4]
LBA[5]
LBA[6]
LBA[7]
Fourth bit expected—Last bit if UP_LEN selects a 4-bit pattern
Fifth bit expected—Last bit if UP_LEN selects a 5-bit pattern
Sixth bit expected—Last bit if UP_LEN selects a 6-bit pattern
Seventh bit expected—Last bit if UP_LEN selects a 7-bit pattern
044—Loopback Deactivate Code Pattern (LBD)
Unused bits are reserved and should be written to 0.
7
6
5
4
3
2
1
0
LBD[1]
LBD[2]
LBD[3]
LBD[4]
LBD[5]
LBD[6]
LBD[7]
—
LBD[1]
First bit expected of LOOPDN pattern
Second bit expected of LOOPDN pattern
Third bit expected of LOOPDN pattern
LBD[2]
LBD[3]
LBD[4]
LBD[5]
LBD[6]
LBD[7]
Fourth bit expected—Last bit if DN_LEN selects a 4-bit pattern
Fifth bit expected—Last bit if DN_LEN selects a 5-bit pattern
Sixth bit expected—Last bit if DN_LEN selects a 6-bit pattern
Seventh bit expected—Last bit if DN_LEN selects a 7-bit pattern
100054E
Conexant
3-41
CONEXANT [ CONEXANT SYSTEMS, INC ]
