I-134
EPSON
S1C88348/317/316/308 TECHNICAL HARDWARE
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Sound Generator)
DUTY0–DUTY2: 00FF45HD4–D6
Selects the duty ratio of the BZ signal.
Table 5.13.6.3 Duty ratio settings
ENRST: 00FF44HD2
Resets the envelope.
When "1" is written: Reset
When "0" is written: No operation
Reading:
Always "0"
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: 00FF44HD1
Controls the addition of an envelope to the BZ
signal.
When "1" is written: ON
When "0" is written: OFF
Reading:
Valid
By writing "1" to ENON, an envelope can be added
to BZ signal output. When "0" is written, an
envelope is not added and the BZ 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).
ENRTM: 00FF44HD3
Selects the envelope attenuation time that is added
to the BZ signal.
When "1" is written: 1.0 sec
(125 msec
× 7 = 875 msec)
When "0" is written: 0.5 sec
(62.5 msec
× 7 = 437.5 msec)
Reading:
Valid
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: 00FF44HD4
Selects the output duration width of the one-shot
buzzer.
When "1" is written: 125 msec
When "0" is written: 31.25 msec
Reading:
Valid
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).
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).
Level
Level 1 (Max)
Level 2
Level 3
Level 4
Level 5
Level 6
Level 7
Level 8 (Min)
12/28
11/28
10/28
9/28
8/28
7/28
6/28
5/28
4096.0
2048.0
3276.8
1638.4
2730.7
1365.3
2340.6
1170.3
DUTY0
DUTY2
DUTY1
8/20
7/20
6/20
5/20
4/20
3/20
2/20
1/20
0
1
0
1
0
1
0
1
0
1
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
12/24
11/24
10/24
9/24
8/24
7/24
6/24
5/24
0
1
0
1
Duty ratio by buzzer frequencies (Hz)