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
4.2.4.3.3 Adjust Detector Band Width (Task 6)
The default bandwidth can be increased or decreased in increments of approximately 0.2% by loading a small
positive or negative (2’s complement) value in register $8E and then issuing task 6. For the standard TIA tone
set the default BW setting is recommended – so there is no need to adjust it. By default, the detector has a
small BW hysteresis to minimize chatter in marginal conditions.
4.2.4.3.4 Adjust No Tone Timer Duration (Task 7)
The default no tone timer duration can be increased or decreased in increments of 60µs by loading a positive
or negative (2’s complement) value in register $8E and then issuing task 7.
Argument = INT (0.5 + 16.667 ⋅TimerDelta)
Where TimerDelta is the amount by which you want to increase or decrease the Default No Tone Timer in
milliseconds.
For example, to increase the default no tone timer by 10ms, load 167 (0xA7) into register $8E before issuing
task 7.
$8E 0x00A7
$93 0x67
// Task 7 command to adjust no tone timer with IRQ’s enabled
4.2.4.4 TX Configuration
4.2.4.4.1 Select Sub-Audio Tone From Preprogrammed List (Task 8)
To select a preprogrammed sub-audio tone, load the index argument (1 to 50) in register $95 then issue
task 8.
For example to set up TX tone to 114.8 Hz, the required C-BUS sequence would be
$95 0x11
$93 0x48
4.2.4.4.2 Program User Defined TX Sub-Audio Tone (Task 9)
To program a user defined sub-audio tone, load the argument in register $8E then issue task 9. Where the
argument is defined by,
Argument
=
INT
0.5
+
36 ⋅ 65536
100000
⋅
f
For example to set up TX tone to 65 Hz, the required C-BUS sequence would be
$8E 0x05FE
$93 0x49
4.2.4.4.3 Program Audio Frequency Ringing Tone (Task 10)
To program a user-defined audio ringing tone, load the argument in register $8E then issue task 10. Where
the argument is defined by,
Argument
=
INT
0.5
+
6
⋅ 65536 ⋅
100000
f
For example to set up the ringing tone frequency to 620 Hz, the required C-BUS sequence would be
$8E 0x0986
$93 0x4A
4.2.4.4.4 Program TX Timer (Task 11)
Load the argument in register $8E, then issue task 11. Where the argument is defined by, the number of 4ms
time units,
Argument
=
INT 0.5
+
4
T
⋅10−
3
For example, to set up a recurring 10s TX timer with IRQ enabled set the argument to 2500 = 0x09C4 (at
each IRQ the sub-audio status in binary is x111 1111, TX timer status is cleared to zero after reading status
register).
$8E 0x09C4
$93 0x4B
2003 CML Microsystems Plc
23
D/838/8
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