Telephone Signalling Transceiver / Least Cost Router
CMX860
1.5.12.7
Analogue Signal Path Register: 8-bit write-only.
This register controls the routing of the analogue signal paths and controls the output drivers.
Analogue Signal Path Register
'C-BUS' address $EC
Bit:
7
0
6
0
5
0
4
3
2
1
0
Line Driver
Mode
Phone Driver
Mode
Input
Selector
Control
Bits 7-5 of the Analogue Signal Path Register are reserved for future use and should be set to 0.
Analogue Signal Path Register b4-3: Line Driver Mode
These bits control the complementary Line Driver and select the signal to be transmitted.
b4
0
b3
0
Line Driver Mode
Off / High Impedance
0
1
1
1
0
1
Transmit Phone-derived Signal
Transmit CMX860 Generated Signal
Transmit Bias Level
Analogue Signal Path Register b2-1: Phone Driver Mode
These bits control the complementary Phone Driver and select the signal to be transmitted.
b2
0
b1
0
Phone Driver Mode
Off / High Impedance
0
1
1
1
0
1
Transmit Line-derived Signal
Transmit CMX860 Generated Signal
Transmit Bias Level
Analogue Signal Path Register b0: Input Selector Control
This bit selects between the Line and Phone as inputs to the CMX860’s decoders/detectors. Note: both
op-amps remain powered up even when not selected (unless device is powersaved).
b0 = 1
b0 = 0
Line-derived signal to decoders/detectors
Phone-derived signal to decoders/detectors
Notes:
1.
2.
‘Line-derived signal’ means the signal at the output of the Line input op-amp. ‘Phone-
derived signal’ means the signal at the output of the Phone input op-amp. The ‘CMX860
Generated Signal’ means the signal from the DTMF/Tones or FSK generators.
When the device is put into Powersave by setting Bit 8 of the General Control Register to
1, the transmit drivers and receive op-amps are powersaved and their outputs go high
impedance. The settings of the Analogue Signal Path Register are unaffected, however.
ã 2002 Consumer Microcircuits Limited
29
D/860/5
CMLMICRO [ CML MICROCIRCUITS ]
