W925E240 Datasheet, PDF (48/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
C1 C2 C3 C4
R1 _{1 2 3 A}
Row/Col
R1
R2
R2 _{4 5 6 B}
R3
R4
R3 _{7 8 9 C}
C1
C2
R4 _{* 0 # D}
C3
C4
Figure 6-11 The Relation Between DTMF and Keypad
Frequency
697 Hz
770 Hz
852 Hz
941 Hz
1209 Hz
1336 Hz
1477 Hz
1633 Hz
Bit:
7
6
5
4
-
DTGE HE
LE
Mnemonic: DTMFG
L1
L0
H1
H0
x
x
0
0
x
x
0
1
x
x
1
0
x
x
1
1
0
0
x
x
0
1
x
x
1
0
x
x
1
1
x
x
LE: Enable low group frequency output.
HE: Enable high group frequency output.
DTGE: Enable dual tone output to DTMF pin.
3
2
1
0
L1
L0
H1
H0
Address: BAh
SELECTED TONE
1209Hz
1336Hz
1477Hz
1633Hz
697Hz
770Hz
852Hz
941Hz
6.12 FSK Generator
W925E/C240 provides a FSK generator, which outputs the FSK signal to the DTMF pin. The FSK
output share with DTMF output pin. It can out FSK signal with 1200Hz baud rate of ITU-T V.23 or
Bellcore 202 signal. A FSK transmit data register (FSKTB) specifies the desired output data. The FSK
Transmit Control Register (FSKTC) can control whether the FSK signal will be output or not. The
relation timing is shown in Figure 6-12
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