Baseband Signal Processor
4
MX829 PRELIMINARY INFORMATION
2. Signal List
PIN NO
1
2
3
SIGNAL
XTAL
XTAL/CLOCK
SERIAL CLOCK
TYPE
DESCRIPTION
output Inverted output of the on-chip oscillator.
input
input
Input to the on-chip oscillator, for external Xtal circuit or clock.
"C-BUS" serial clock input. This clock, produced by the µController, is used for
transfer timing of commands and data to and from the device. See section
7.1.4
"C-BUS" serial data input from the µController. Data is loaded into this device
in 8-bit bytes, MSB (B7) first, and LSB (B0) last, synchronized to the SERIAL
CLOCK. See section 7.1.4.
"C-BUS" serial data output to the µController. The transmission of REPLY
DATA bytes is synchronized to the SERIAL CLOCK under the control of the
CS
input. This 3-state output is held at high impedance when not sending
data to the µController. See section 7.1.4.
"C-BUS" data loading control function: this input is provided by the µController.
Data transfer sequences are initiated, completed or aborted by the
CS
signal.
See section 7.1.4.
This output indicates an interrupt condition to the µController by going to a
logic "0". This is a "wire-ORable" output, enabling the connection of up to 8
peripherals to 1 interrupt port on the µController. This pin has a low
impedance pulldown to logic "0" when active and a high-impedance when
inactive. An external pull-up resistor is required. The conditions that cause
interrupts are indicated in the STATUS register and are effective if not masked
out by a corresponding bit in the CONTROL register. The reading of the
Status Register resets the IRQ to a high impedance and sets the contents of
the Status Register to 0.
The carrier detect output for the MSK Rx.
The carrier detect integrating capacitor.
A bias line for the internal circuitry, held at V
DD
/2. This pin must be bypassed
to a capacitor mounted close to the device pins.
AC coupled Tx audio input (external amplification is required for use as a
microphone input).
Negative supply (ground).
AC coupled inverting input to the Rx input amplifier (AMP1).
Output of the Rx input amplifier (AMP1)
Output of the audio filter/limiter section. In powersave mode this output is
connected to V
BIAS
via a 500kΩ resistor.
The 1200 or 2400 baud MSK Tx output and the DTMF encoder output. When
enabled but not transmitting MSK or DTMF signals, or when in powersave
mode, this output is connected to V
BIAS
via a 500kΩ resistor. On power-up,
this output can be any level: a General Reset command is required to ensure
that this output attains V
BIAS
initially.
Input to the audio summing amplifier (AMP2).
Output of the audio summing amplifier (AMP2).
Input to MOD1 audio gain control.
Input to the audio volume control.
Output of the audio volume control.
Output of MOD1 audio gain control.
Output of MOD2 audio gain control.
Positive supply. Levels and voltages are dependent upon this supply. This pin
should be bypassed to V
SS
by a capacitor.
4
COMMAND DATA
input
5
REPLY DATA
output
6
CS
input
7
IRQ
output
8
9
10
11
12
13
14
15
16
CARRIER DETECT
CD CAP
V
BIAS
MIC
V
SS
DEMOD IN
DEMOD FB
FILTER OUT
MSK/DTMF OUT
output
output
output
input
Power
input
output
output
output
17
18
19
20
21
22
23
24
SUM IN
SUM OUT
MOD1 IN
VOL IN
AUDIO OUT
MOD1
MOD2
V
DD
input
output
input
input
output
output
output
Power
© 1998 MX•COM Inc.
www.mxcom.com Tele: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480160.004
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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CMLMICRO [ CML MICROCIRCUITS ]
