Audio Signaling Processor
Page 5 of 26
MX803A PRELIMINARY INFORMATION
Pin No.
18
Name
Type
Description
CAL/CUES Out Output An auxiliary, selectable tone frequency output, providing a square wave
CALibration signal from the Tone 2 Generator or a sine wave CUES
(beep) signal from the Summing Amplifier. The output mode (CAL or
CUES) is selected by Bit 14 in the TX Tone Generator 2 Register
(Table 7). When Tone Generator 2 is set to Notone, the CAL input is
pulled to V
BIAS
; during a powersave of Tone Generator 2 it is held at V
SS
.
Sum in
Input
Input to the on-chip Summing Amplifier. This amplifier is available for
combining Tone 1 and Tone 2 outputs (DTMF). Gain and coupling
components should be used at this input to provide the required system
gains. See Figure 2 and Figure 3
19
20
21
Sum Out
Switched Sum
Out
Serial Clock
Output Output of the on-chip summing amplifier. Combined tones (1 and 2) are
available at this output. See Figure 2 and Figure 3.
Output This is the combined tone output available for transmitter modulation.
The switch allows control of the MX803A output. Control of this switch is
by Bit 4 of the Control Register. See Figure 2 and Figure 3.
Input
C-BUS serial clock input. This clock, produced by the
µC,
is used for
transfer timing of commands and data to and from the MX803A.
See Figure 8 and Figure 9.
23
24
V
DD
Power Positive supply. A single +5 volt power supply is required. Levels and
voltages within this Audio Signaling Processor are dependent upon this
supply..
No Internal Connection. These pins may be connected to V
SS
to improve
screening and reduce noise levels around the MX803A.
Table 1: Signal List
8, 9, 22
N/C
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