HD404654 Datasheet, PDF (82/111 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404654 Series
Tone Generator Mode Register (TGM: $019): Four-bit write-only register, which controls output
frequencies as shown in figure 65, and is reset to $0 by MCU reset.
Tone generator mode register (TGM: $019)
Bit
Initial value
Read/Write
Bit name
3
0
W
TGM3
2
0
W
TGM2
1
0
W
TGM1
0
0
W
TGM0
TGM3
0
0
1
1
TGM2
0
1
0
1
TONEC output frequencies
f_C1 (1,209 Hz)
f_C2 (1,336 Hz)
f_C3 (1,477 Hz)
f_C4 (1,633 Hz)
TGM1
0
0
1
1
TGM0
0
1
0
1
TONER output frequencies
f_R1 (697 Hz)
f_R2 (770 Hz)
f_R3 (852 Hz)
f_R4 (941 Hz)
Figure 65 Tone Generator Mode Register (TGM)
Tone Generator Control Register (TGC: $01A): Three-bit write-only register, which controls the
start/stop of the DTMF signal output as shown in figure 66, and is reset to $0 by MCU reset. TONER and
TONEC output can be independently controlled by bits 2 and 3 (TGC2, TGC3), and the DTMF circuit is
controlled by bit 1 (TGC1) of this register.
Tone generator control register (TGC: $01A)
Bit
Initial value
Read/Write
Bit name
3
0
W
TGC3
2
0
W
TGC2
1
0
W
TGC1
0
—
—
Not used
TGC3
0
1
TONEC output control (column)
No output
TONEC output (active)
TGC1
0
1
DTMF enable bit
DTMF disable
DTMF enable
TGC2
0
1
TONER output control (row)
No output
TONER output (active)
Figure 66 Tone Generator Control Register (TGC)
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