FRS Signalling Processor
CMX882
Voice Processing Combinations
Table 1 shows the valid voice processing combinations.
Table 1 Voice Processing Combinations
TX
RX
De-Scramble Expand
Compress
Scramble Pre-Emphasis
Filter
3
Filter
3
De-Emphasis
1
2
3
4
5
6
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Not Valid
3
3
3
3
3
3
3
3
3
3
3
7
Not Recommended
81
3
3
Host Interface
A serial data interface (C-BUS) is used for command, status and data transfers between the CMX882 and
the host µC; this interface is compatible with microwire, SPI etc. Interrupt signals notify the host µC when
a change in status has occurred and the µC should read the status register across the C-BUS and
respond accordingly. Interrupts only occur if the appropriate mask bit has been set. See section 1.6.15.
Auxiliary (Signal Monitor) analogue signal
The CMX882 includes a Signal level monitor. This is an 8-bit successive approximation ADC and a two
level signal sensor. The two level sensor facility can be used in conjunction with the power saving mode
to wake up powered down blocks, and issue an interrupt on the IRQN line when the Signal exceeds the
preset threshold level. The auxiliary ADC voltage reference is taken directly from the VDD(A) supply, so
the Signal level being monitored should be derived from this supply voltage.
1 Audio quality is somewhat degraded.
2004 CML Microsystems Plc
15
D/882/7
CMLMICRO [ CML MICROCIRCUITS ]
