CS61581
2.15 Control Register 2 LH: Address 0x11
7 (MSB)
AIS
6
RAMPLSE
5
MATCHZ
4
LOOPDN
3
LOOPUP
2
RPWDN
1
TxHIZ
0 (LSB)
SH/LH
AIS
RAMPLSE
MATCHZ
LOOPDN
LOOPUP
RPWDN
TxHIZ
SH/LH
Alarm Indication Signal.
AIS = 1 when an all ones pattern is present at the receiver. This bit is reset to “0” by the first
read occurring after the AIS condition has cleared.
An interrupt will occur when AIS is present unless a “1” is written to AIS disabling the interrupt.
When RAMPLSE = 1, output pulse shapes are determined by the codes in the internal, pro-
grammable, transmit RAM.
Matched Impedance Drive
When MATCHZ = 1 the output impedance is automatically set to match the impedance of a
standard T1 or E1 line.
A 1:1.5 transformer should be used when MATCHZ = 1, and a 1:2 transformer should be used
when MATCHZ = 0. (See Figures 15 and 16.)
Loop Down
In Long Haul mode, setting LOOPDN to “1” causes the data pattern 001001... to be repetitively
transmitted.
Loop Up
In Long Haul mode, setting LOOPUP to “1” causes the data pattern 0000100001... to be repetitively
transmitted.
Receiver Power Down
When RPWDN = 1, the receiver circuitry is powered down, but the transmitter is still active.
Transmitter High Impedance
When TxHIZ = 1 the transmitter goes to a low-power, high-impedance state
Short Haul / Long Haul Select
When SH/LH = 0, the CS61581 is in the Long Haul mode.
When SH/LH = 1, the CS61581 is in the Short Haul mode. Note that it overwrites the E1_LH bit,
if set.
SH/LH controls the functions of the bits in Control Register 1 (address 0x10) and Control Reg-
ister 2 (address 0x11).
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DDS2S1211P1PF18