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DUTY0–DUTY2: 00FF45H•D4–D6
Selects the duty ratio of the buzzer signal.
Level
DUTY2
Level 1 (Max)
0
Level 2
0
Level 3
0
Level 4
0
Level 5
1
Level 6
1
Level 7
1
Level 8 (Min)
1
The buzzer sound level can be adjusted by selecting the duty ratio from among the
above 8 types. However, when the envelope has been set to ON (ENON = "1"), this
setting becomes invalid.
At initial reset, this register is set to "0" (level 1).
ENRST: 00FF44H•D2
Resets the envelope.
When "1" is written: Reset
When "0" is written: No operation
Reading:
The envelope is reset by writing "1" to ENRST and
the duty ratio returns to level 1 (maximum).
Writing "0" to ENRST and writing "1" when an
envelope has not been added become invalid. Since
ENRST is exclusively for writing, it always becomes
"0" during reading.
ENON: 00FF44H•D1
Controls the addition of an envelope to the buzzer
signal.
When "1" is written: ON
When "0" is written: OFF
Reading:
By writing "1" to ENON, an envelope can be added
to buzzer signal output. When "0" is written, an
envelope is not added and the buzzer signal is fixed
at the duty ratio selected in DUTY0–DUTY2.
At initial reset and when "1" is written to BZSHT,
ENON is set to "0" (OFF).
E0C88832/88862 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Sound Generator)
Table 5.12.6.3 Duty ratio settings
DUTY1
DUTY0
4096.0
2048.0
0
0
0
1
1
0
1
1
0
0
0
1
1
0
1
1
Always "0"
Valid
Duty ratio by buzzer frequencies (Hz)
3276.8
2730.7
1638.4
1365.3
8/16
8/20
12/24
7/16
7/20
11/24
6/16
6/20
10/24
5/16
5/20
9/24
4/16
4/20
8/24
3/16
3/20
7/24
2/16
2/20
6/24
1/16
1/20
5/24
ENRTM: 00FF44H•D3
Selects the envelope attenuation time that is added
to the buzzer signal.
When "1" is written: 1.0 sec
When "0" is written: 0.5 sec
Reading:
The attenuation time of the digital envelope is
determined by the time for changing the duty ratio.
The duty ratio is changed in 125 msec (8 Hz) units
when "1" is written to ENRTM and in 62.5 msec (16
Hz) units, when "0" is written.
This setting becomes invalid when an envelope has
been set to OFF (ENON = "0").
At initial reset, ENRTM is set to "0" (0.5 sec).
SHTPW: 00FF44H•D4
Selects the output duration width of the one-shot
buzzer.
When "1" is written: 125 msec
When "0" is written: 31.25 msec
Reading:
The one-shot buzzer output duration width is set to
125 msec when "1" is written to SHTPW and 62.5
msec, when "0" is written.
At initial reset, SHTPW is set to "0" (31.25 msec).
EPSON
2340.6
1170.3
12/28
11/28
10/28
9/28
8/28
7/28
6/28
5/28
(125 msec × 7 = 875 msec)
(62.5 msec × 7 = 437.5 msec)
Valid
Valid
107
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