
S1C88409 TECHNICAL MANUAL
EPSON
153
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (Sound Generator)
5.15.6 I/O memory of sound generator
Table 5.15.6.1 shows the sound generator control bits.
Table 5.15.6.1 Sound generator control bits
Address
Function
R/W
Init
0
1
Comment
Name
Bit
00FF54
–
One-shot buzzer forcibly stop
One-shot buzzer trigger/status
One-shot buzzer duration width selection
Envelope attenuation time
Envelope reset
Envelope On/Off control
Buzzer output control
–
W
R
W
R/W
W
R/W
–
0
–
0
–
No operation
Ready
No operation
31.25 msec
0.5 sec
No operation
Off
–
Forcibly stop
Busy
Trigger
125 msec
1 sec
Reset
On
"0" when being read
1
–
BZSTP
BZSHT
SHTPW
ENRTM
ENRST
ENON
BZON
D7
D6
D5
D4
D3
D2
D1
D0
1 ENON is reset to "0" during one-shot output.
00FF55
–
Buzzer signal duty ratio selection
–
Buzzer frequency selection
–
R/W
–
R/W
–
0
–
0
–
"0" when being read
–
DUTY2
DUTY1
DUTY0
–
BZFQ2
BZFQ1
BZFQ0
D7
D6
D5
D4
D3
D2
D1
D0
0
1
DUTY2–1
Buzzer frequency (Hz)
2
0
1
0
1
0
1
0
1
0
1
0
1
0
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
4096.0
2048.8
8/20
7/20
6/20
5/20
4/20
3/20
2/20
1/20
3276.8
1638.4
12/24
11/24
10/24
9/24
8/24
7/24
6/24
5/24
2730.7
1365.3
12/28
11/28
10/28
9/28
8/28
7/28
6/28
5/28
2340.6
1170.3
BZFQ2
0
1
BZFQ1
0
1
0
1
BZFQ0
0
1
0
1
0
1
0
1
Frequency (Hz)
4096.0
3276.8
2730.7
2340.6
2048.0
1638.4
1365.3
1170.3
BZON: Buzzer output control register
(00FF54HD0)
Controls the BZ signal output.
When "1" is written: BZ signal output
When "0" is written: HIGH level (DC) output
Reading: Valid
BZON is the output control register for BZ signal.
When "1" is set, the BZ signal is output from the
output port terminal R42 and when "0" is set, high
(VDD) level is output. At this time, the high-
impedance control register of the output port R42
must be set to "0" and the data register must be set
to "1".
At initial reset, BZON is set to "0" (high level
output).
BZFQ0–BZFQ2: Buzzer frequency selection
register (00FF55HD0–D2)
Selects the BZ signal frequency.
Table 5.15.6.2 Buzzer frequency settings
BZFQ2
Buzzer frequency (Hz)
0
1
4096.0
3276.8
2730.7
2340.6
2048.0
1638.4
1365.3
1170.3
BZFQ1
0
1
0
1
BZFQ0
0
1
0
1
0
1
0
1
The buzzer frequency can be selected from among
the above 8 types that have divided the OSC1
clock.
At initial reset, the BZFQ register is set to "0"
(4096.0 Hz).