Telephone Signalling Transceiver / Least Cost Router
CMX860
1.5.12.9
Programming Register (includes generation & detection of 2130 and 2750 Hz)
Programming Register : 16-bit write-only.
'C-BUS' address $E8
This register is used to program the transmit and receive programmed tone pairs by writing appropriate
values to RAM locations within the CMX860. Note that these RAM locations are cleared by Powersave or
Reset.
The Programming Register should only be written to when the Programming Flag bit (b13) of the Status
Register is 1. The act of writing to the Programming Register clears the Programming Flag bit. When the
programming action has been completed (normally within 150ms) the CMX860 will set the bit back to 1.
When programming Transmit or Receive Tone Pairs, do not change the Transmit or Receive Mode
Registers until programming is complete and the Programming Flag bit has returned to 1.
Transmit Tone Pair Programming
4 transmit tone pairs (TA to TD) can be programmed.
The frequency (max 3.4kHz) and level must be entered for each tone to be used.
Single tones are programmed by setting both level and frequency values to zero for one of the pair.
Programming is done by writing a sequence of up to seventeen 16-bit words to the Programming
Register.
The first word should be 32768 (8000 hex), the following 16-bit words set the frequencies and levels and
are in the range 0 to 16383 (0-3FFF hex)
Word
Tone
Pair
Value written
Default
Setting
1
2
3
4
5
32768
Tone 1 frequency
Tone 1 level
Tone 2 frequency
Tone 2 level
Tone 1 frequency
Tone 1 level
- - - - - - - - - -
- - - - - - - - - -
Tone 1 frequency
Tone 1 level
Tone 2 frequency
Tone 2 level
TA
TA
TA
TA
TB
TB
- - -
- - -
TD
TD
TD
TD
6
7
- - -
- - -
14
15
16
17
2130 Hz
-20 dBm
2750 Hz
-20 dBm
NB. Tone Pair TD is configured as
2130 and 2750 Hz by default, but
can be re-programmed if required.
The Frequency values to be entered are calculated from the formula:
Value to be entered = desired frequency (Hz) * 3.414
i.e. for 1kHz the value to be entered is 3414 (or 0D56 in Hex).
The Level values to be entered are calculated from the formula:
Value to be entered = desired Vrms * 93780 / AVDD
i.e. for 0.5Vrms at AVDD = 3.0V, the value to be entered is 15630 (3D0E in Hex)
ã 2002 Consumer Microcircuits Limited
33
D/860/5
CMLMICRO [ CML MICROCIRCUITS ]
