TS7514 查看數據表（PDF） - STMicroelectronics
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TS7514 Datasheet PDF : 19 Pages
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TS7514
OPERATING MODES
The various operating modes are defined by
MC/BC and MOD/DTMF inputs, and by the content
of a control register RPROG.
The TS7514 includes 8 control registers. Access to
each control register is achieved through an auxil-
liary 8-bit shift register (input register). The input of
that shift register is connected either to TxD or
PRD, depending upon the statusof theENP control
pin (ie when ENP = 0 and ENP = 1 respectively).
In both cases, the RTS input receivesthe shift clock
and sequentialy transfer is controlled by setting
simultaneously MOD/DTMF and MC/BC to 0. The
previous internal status and data are memorized
during loading of the input register so that transmis-
sion continues properly. That feature allows the
user to modify transmission level or line monitoring
selection during transmission. The transmit chan-
nel operatingmode (Modem main or back channel,
DTMF) can only be modified when RTS = 1. When
RTS = 0, the ATO transmit output is enabled and
the preselected operatingmode is activated. When
RTS returns to 1, Modem or DTMF transmission is
inhibited after the first zero crossing of the gener-
ated signal.
MOD/DTMF
1
1
0
0
MC/BC
1
0
1
0
Transmission (ATO)
Reception (RxD, DCD)
MODEM, Main Channel
MODEM, Back Channel
MODEM, Back Channel
MODEM, Main Channel
DTMF
DCD= Active Tone Detection (270 -500Hz) if RTS = 1…
DCD = 1 if RTS = 0
If RTS = 0 when that configuration occurs, transmission and reception are not modified.
If RTS = 1 (no signal sent on the line), transmission is not modified and reception is set
up to detect 2100Hz tone (note 1).
Note 1 : The decision threshold of the demodulator output is shifted, so that RxD changes from 0 to 1 at 1950Hz instead of 1700Hz.
MODEM TRANSMISSION FREQUENCIES
Modulation
Rate
TxD
75bps
1
0
1200bps
1
0
CCITT R35 AND V.23
Recommendations (Hz)
390 ±2
450 ±2
1300 ±10
2100 ±10
Frequency Generated with
Xtal at 3.579MHz (Hz)
390.09
450.45
1299.76
2099.12
Error (Hz)
+0.09
+0.45
-0.24
-0.88
DTMF TRANSMISSION FREQUENCIES
Specifications
DTMF (Hz)
f1
697 ±1.8%
f2
770 ±1.8%
f3
852 ±1.8%
f4
941 ±1.8%
f5
1209 ±1.8%
f6
1336 ±1.8%
f7
1477 ±1.8%
f8
1633 ±1.8%
Frequency Generated with
Xtal at 3.579MHz (Hz)
699.13
771.45
853.90
940.01
1209.31
1335.65
1479.15
1627.07
Dividing Ratio
5120
4640
4192
3808
2960
2680
2420
2200
Error (%)
+0.31
+0.19
+0.22
-0.10
+0.03
-0.03
+0.15
+0.36
6/19
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