CMX838 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX838' PDF : 71 Pages View PDF
FRS/PMR446/GMRS Family Radio Processor
CMX838
TONE SIGNALING CONTROL REGISTER ($93): 01001000b = $48
• Enable power for subaudio section (01)
• No IRQ (00)
• Load ‘select subaudio tone from preprogrammed list’ task (1000)
TONE SIGNALING CONTROL REGISTER ($93): 01000000b = $40
• Enable power for subaudio section (01)
• No IRQ (00)
• Load ‘normal operation’ task (0000)
SUBAUDIO ANALOG CONTROL ($97): 00010000 00010000b = $1010
• Subaudio encoder output passed to subaudio filter input (0)
• Subaudio LPF gain set to 0dB (default for Tx mode) (0)
• Subaudio LPF configured as 2kHz smoothing filter (0)
• Tx subaudio level set to 0.0dB (10000)
• Tx subaudio filter gain counter set to 0 for normal operation (0)
• Subaudio filter configuration set to 0 for normal operation (0)
• DC restoration set to 0 for normal operation (0)
• Rx subaudio level set to 0.0dB (10000)
MICOUT 3
MICIN 4
-
+
Vbias
AUX I/O 2
RXIN 1
VDD 22
VSS 19
VBIAS 26
XTAL 12
XTAL 13
REFIN 11
+RFIN 9
-RFIN 8
VDD
VSS
Bias
+
-
preemph
HPF
BOUT AOUT
27 28
AIN
BIN
25 24
LIM
LPF
voltage ref
LPF
Vbias
BPF
LPF
CTCSS encode
audio tone encode
1
0
CTCSS decoders
voltage
ref
RX Notone / TX Duration
timer
+
Vbias
Vbias
Vbias
deemph
0°/180°
phase
0°/180°
phase
CBUS
serial
interface
Baseband timing generation
divide
32/33
12 bit programmable
reference counter
programmable divider
phase
detect
lock
detect
voltage ref
charge
pump
SVDD
SVSS
s
RXOUT 23
TXMOD1 21
TXMOD2 20
IRQ 15
RPLY DATA 16
CMD DATA 17
SERIAL CLOCK 18
CS 14
SVDD 7
SVSS 10
CPOUT 5
ISET 6
Figure 47: Application Example TX, Subaudio Encoding, Single Point Modulation
6.6.3 RX, subaudio decode CTCSS tone or tones
This RX scenario configures the CMX838 for:
• Baseband clock generation from RF synthesizer clock
• Rx Enabled
• Input from Rx In pin
• Signal passed through LPF, HPF, and de-emphasis in audio path (limiter bypassed)
• CTCSS decoder enabled with a tone ‘watch list’ configured, if desired
6.6.3.1 Register Descriptions:
GENERAL RESET ($01): (if required)
2003 CML Microsystems Plc
60
D/838/8
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