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CHAPTER 20 BUZZER OUTPUT FUNCTIONS
User’s Manual U12697EJ3V0UM
20.3 Control Registers
The buzzer output function is controlled by the following two registers.
•
Clock output control register (CKS)
•
Port 2 mode register (PM2)
(1) Clock output control register (CKS)
This register sets the frequency of the buzzer output.
CKS is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets CKS to 00H.
Remark
CKS has the function of setting the clock for PCL output except for the buzzer output frequency
setting.
Figure 20-2. Format of Clock Output Control Register (CKS)
Address: 0FF40H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
CKS
BZOE
BCS1
BCS0
CLOE
CCS3
CCS2
CCS1
CCS0
BZOE
Buzzer output buzzer
0
Stop buzzer output
1
Start buzzer output
BCS1
BCS0
Buzzer output frequency selection
0
0
f
XX
/2
10
(12.2 kHz)
0
1
f
XX
/2
11
(6.1 kHz)
1
0
f
XX
/2
12
(3.1 kHz)
1
1
f
XX
/2
13
(1.5 kHz)
CLOE
Clock output control (Refer to
Figure 19-3
)
CCS3
CCS2
CCS1
CCS0
Clock output frequency selection
(Refer to
Figure 19-3
)
Remarks 1.
f
XX
: Main system clock frequency (f
X
or f
X
/2)
2.
f
X
:
Main system clock oscillation frequency
3.
Figures in parentheses apply to operation with f
XX
= 12.5 MHz.
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