RFX144V24-S23 and RFX96V24-S23 Modem Designer’s Guide
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3-9
Table 3-1. Interface Memory Bit Definitions (Cont'd)
Mnemonic
Location
Default
Name/Description
DTDET
1C:6
–
Dual Tone Detected. When configured as an DTMF receiver, the modem sets status bit DTDET to a 1
when a signal is received that satisfies all DTMF criteria except on-time, off-time, and cycle-time. The
encoded DTMF Output Word (1C:0-3) value is available when DTDET is a 1. If the received signal is a
valid DTMF signal, then DTDET will be set to a 1 approximately 11 ms following EDET setting to a 1.
The DTDET bit is reset by the modem after DTMFD is set to a 1 or if the received signal fails to satisfy
any subsequent DTMF criteria.
DTDETC
17:6
0
Dual Tone Detected Copy. In DTMF modes, DTDETC is a copy of the DTDET bit for programmable
interrupt control.
DTMF
1C:0-3
–
DTMF Output Word. When configured as an DTMF receiver and a DTMF signal is present such that
status bit DTDET is set by the modem, the encoded DTMF output is written to 1C:0-3. The DTMF
symbol codes are:
DTMF
Encoded
DTMF
Encoded
Symbol
Output (Hex)
Symbol
Output (Hex)
1
0
3
8
4
1
6
9
7
2
9
A
*
3
#
B
2
4
A
C
5
5
B
D
8
6
C
E
0
7
D
F
DTMFD
1C:4
–
DTMF Signal Detected. When configured as an DTMF receiver, the modem sets status bit DTMFD to a
1 when a DTMF signal has been detected that satisfies all specified DTMF detect criteria. The host must
reset this bit after reading the DTMF Output Word (1C:0-7), otherwise two or more detections of the
same symbol may be missed by the host.
DTMFDC
17:4
0
DTMF Detected Copy. In DTMF modes, DTMFDC is a copy of the DTMFD bit for programmable
interrupt control.
ECHOAT
0F:0-1
00
Handset Echo Attenuation. In speakerphone mode, ECHOAT bits control the level of the simulated
echo for handset operation when the SP/HS bit is a 0. The signal entering the XIA ADC is attenuated
and retransmitted to the XIA DAC as follows:
Bit 1
Bit 0
Attenuation
0
0
∞
dB
0
1
18 dB
1
0
12 dB
1
1
6 dB
EDET
1C:7
–
DTMF Early Detection. When configured as an DTMF receiver, the modem sets status bit EDET to a 1
approximately 20 ms after the DTMF signal energy is detected to indicate that the received signal is
probably a DTMF signal. This bit is reset by the modem after DTMFD is set to a 1 or if the received
signal fails to satisfy any subsequent DTMF criteria.
EDETC
17:7
0
Early Detection Copy. In DTMF modes, EDETC is a copy of the EDET bit for programmable interrupt
control.
ENUPDT
14:5
0
Energy Update. When the Classifier AGC is enabled (AGCSEL = 1) and control bit ENUPDT is a 1 ,
the AGC gain will be adjusted whenever the input signal energy exceeds the AGC Gain Adaptation
Threshhold parameter value. (Voice/Audio Codec Mode.)
Summary of Contents for RFX144V24-S23
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