351
DTCR—DTMF control register
H'B2
DTMF generator
Bit
Initial value
Read/Write
7
DTEN
0
R/W
6
—
1
—
5
CLOE
0
R/W
4
RWOE
0
R/W
3
CLF1
0
R/W
0
RWF0
0
R/W
2
CLF0
0
R/W
1
RWF1
0
R/W
DTMF row signal output frequency 1 and 0
RWF0
0
1
0
1
DTMF row signal output frequency
697 Hz (R1)
770 Hz (R2)
852 Hz (R3)
941 Hz (R4)
Row output enable
0
1
DTMF row signal output is disabled (high-impedance)
DTMF row signal output is enabled
RWF1
0
1
DTMF column signal output frequency 1 and 0
CLF0
0
1
0
1
DTMF column signal output frequency
1209 Hz (C1)
1336 Hz (C2)
1447 Hz (C3)
1633 Hz (C4)
CLF1
0
1
Column output enable
0
1
DTMF column signal output is disabled (high-impedance)
DTMF column signal output is enabled
DTMF generator enable
0
1
DTMF generator is halted
DTMF generator operates