AM79C32A Advanced Micro Devices, AM79C32A Datasheet - Page 27

• Manufacturer Part Number: AM79C32A
• Description: Digital Subscriber Controller (DSC) Circuit
• Manufacturer: Advanced Micro Devices

The output frequency of the DTMF tone generator ap-
proximately equals:
where i is the decimal equivalent of value programmed
into the FTGR register. This allows the DTMF genera-
tor to supply common dual tone call progress signals
such as Busy or Dial tones.
Note:
These coefficients do not apply to the DTMF generator.
DTMF Frequency in Hz
Table 22. Tone Ringer and Tone Generator
Frequency (Hz)
2666
2000
1600
1333
1142
1000
889
800
727
667
615
571
533
500
471
444
421
400
381
364
348
333
320
Frequency Coefficients
=
--------------------------------------------------- -
integer 8192 i
64000
Hex Code
AB
1D
81
67
56
4A
41
39
34
2F
2B
28
25
23
21
1F
1B
1A
19
18
17
16
15
+
Am79C30A/32A Data Sheet
1
The ATGR registers allow the user to program a gain of
–18 dB to 0 dB in 2-dB steps. Example ATGR codes to
obtain amplitude gains are listed in Table 23. 0 dB im-
plies a level of +3 dBm0. The gain values are rounded
off to the nearest 1 dB.
Note:
See the amendment to Table 23 following page 100.
Secondary Tone Ringer
A Secondary Tone Ringer is included, which is able to
ring the phone using the LS outputs while a voice con-
versation is in progress on the EAR outputs. The STR
is louder than the Tone Generator, and may be used
with or without enabling the MAP in order to provide
flexible control of system power consumption. The STR
is not available if the INIT register is programmed to
Idle or Power-Down mode. The amplitude and fre-
quency of the STR square-wave output waveform is
programmable via the STRA and STRF registers, re-
spectively. If both the LS outputs from the MAP receive
path and the STR are simultaneously enabled, priority
is given to the STR connection. The STR is available for
both the DSC and IDC circuits. A legal value must be
programmed in the STRF register before the STR is
enabled.
Table 23. Amplitude Gain Coefficients
Gain (dB)
–18
–16
–14
–12
–10
–8
–6
–4
–2
0
Hex Code
37
32
31
27
22
21
20
12
11
10
27