FX829 Datasheet, PDF (13/34 Pages) CML Microcircuits – Baseband Signal Processor

Baseband Signal Processor
FX829
DTMFEN
(Bit 6)
When this bit is "1", the DTMF output is enabled.
When this bit is "0", the DTMF output is disabled. As the powersave of the DTMF
is performed in the DTMFHI and DTMFLO registers, this bit allows a fast start up
time for the tones.
Note:
1. The DTMF Encoder and FFSK Tx cannot both be enabled at the same time.
If both DTMFEN and FFSKTX are "1", then they will both be disabled.
DTMFHI
(Bit 5)
When this bit is "1", the DTMF high frequency tone generator is enabled. It will not
appear on the output pin unless or until the DTMFEN is "1".
When this bit is "0", the DTMF high frequency tone generator is disabled (i.e.
powersaved).
DTMFLO
(Bit 4)
When this bit is "1", the DTMF low frequency tone generator is enabled. It will not
appear on the output pin unless or until the DTMFEN is "1".
When this bit is "0", the DTMF low frequency tone generator is disabled (i.e.
powersaved).
DTMF3, DTMF2,
DTMF1, DTMF0
(Bit 3, Bit 2,
Bit 1, Bit 0)
These four bits define the DTMF tones according to the table below:
Bit
Bit
Bit
Bit
3
2
1
0
DTMF
Tones
DTMF
'Digit'
0
0
0
0
1209Hz + 697Hz
1
0
0
0
1
1209Hz + 770Hz
4
0
0
1
0
1209Hz + 852Hz
7
0
0
1
1
1209Hz + 941Hz
*
0
1
0
0
1337Hz + 697Hz
2
0
1
0
1
1337Hz + 770Hz
5
0
1
1
0
1337Hz + 852Hz
8
0
1
1
1
1337Hz + 941Hz
0
1
0
0
0
1478Hz + 697Hz
3
1
0
0
1
1478Hz + 770Hz
6
1
0
1
0
1478Hz + 852Hz
9
1
0
1
1
1478Hz + 941Hz
#
1
1
0
0
1634Hz + 697Hz
A
1
1
0
1
1634Hz + 770Hz
B
1
1
1
0
1634Hz + 852Hz
C
1
1
1
1
1634Hz + 941Hz
D
© 1997 Consumer Microcircuits Limited
13
D/829/4