90
EPSON
S1C63458 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Sound Generator)
4.12.7 I/O memory of sound generator
Table 4.12.7.1 shows the I/O addresses and the control bits for the sound generator.
Table 4.12.7.1 Control bits of sound generator
Address
Comment
D3
D2
Register
D1
D0
Name
Init 1
10
0
4096.0
1
3276.8
2
2730.7
3
2340.6
[BZFQ2, 1, 0]
Frequency (Hz)
4
2048.0
5
1638.4
6
1365.3
7
1170.3
[BZFQ2, 1, 0]
Frequency (Hz)
FF6EH
0
BZFQ2
BZFQ1
BZFQ0
R
R/W
0 3
BZFQ2
BZFQ1
BZFQ0
– 2
0
Unused
Buzzer
frequency
selection
FF6FH
0
BDTY2
BDTY1
BDTY0
R
R/W
0 3
BDTY2
BDTY1
BDTY0
– 2
0
Unused
Buzzer signal duty ratio selection
(refer to main manual)
FF6CH
ENRTM ENRST
ENON
BZE
R/W
W
R/W
ENRTM
ENRST3
ENON
BZE
0
Reset
0
1 sec
Reset
On
Enable
0.5 sec
Invalid
Off
Disable
Envelope releasing time
Envelope reset (writing)
Envelope On/Off
Buzzer output enable
FF6DH
0
BZSTP BZSHT SHTPW
RW
R/W
0 3
BZSTP3
BZSHT
SHTPW
– 2
0
Stop
Trigger
Busy
125 msec
Invalid
Ready
31.25 msec
Unused
1-shot buzzer stop (writing)
1-shot buzzer trigger (writing)
1-shot buzzer status (reading)
1-shot buzzer pulse width setting
*1 Initial value at initial reset
*2 Not set in the circuit
*3 Constantly "0" when being read
BZE: BZ output control register (FF6CHD0)
Controls the buzzer (BZ) signal output.
When "1" is written: BZ output ON
When "0" is written: BZ output OFF
Reading: Valid
When "1" is written to BZE, the BZ signal is output from the BZ terminal.
When "0" is written, the BZ terminal goes to a high (VDD) level.
At initial reset, this register is set to "0".
BZFQ0–BZFQ2: Buzzer frequency selection register (FF6EHD0–D2)
Selects the buzzer signal frequency.
Table 4.12.7.2 Buzzer signal frequency setting
Buzzer frequency (Hz)
4096.0
3276.8
2730.7
2340.6
2048.0
1638.4
1365.3
1170.3
BZFQ0
0
1
0
1
0
1
0
1
BZFQ1
0
1
0
1
BZFQ2
0
1
Select the buzzer frequency from among the above 8 types that have divided the oscillation clock.
At initial reset, this register is set to "0".