FUJITSU F2MC-8L F202RA - Manual (Page 356)

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CHAPTER 15 BUZZER OUTPUT
15.1 Overview of the Buzzer Output
For the buzzer output, four kinds of output frequencies (square waves) can be selected.
The buzzer output may be used for the confirmation tone of key input and other tones.
■ Buzzer Output Function
The buzzer output function is a function for outputting a signal (square wave) used for tones such as a
confirmation tone.
For the buzzer output, it is selectable whether to output one of four output frequencies or to disable the
output.
As the buzzer output, four kinds of divided-frequency outputs are supplied from the time-base timer.
Note:
The time-base timer supplies clock for the buzzer output. Therefore, buzzer output will be affected
when time-base timer is cleared.
Table 15.1-1 lists the four kinds of output frequencies (square waves) specifiable for the buzzer output.
Note:
Calculation example of an output frequency
If time-base timer output F
CH
/2
10
is selected in the buzzer register (BZCR) (BZ2=1, BZ1=0, and
BZ0=0) and the oscillation (F
CH
) is 12.5 MHz, the output frequency being output from the BZ pin is
calculated as follows:
Table 15.1-1 Output Frequencies
Clock supplier Buzzer output Square wave output (at 12.5 MHz)
time-base timer
2
13
/F
CH
F
CH
/2
13
(1.526 kHz)
2
12
/F
CH
F
CH
/2
12
(3.052 kHz)
2
11
/F
CH
F
CH
/2
11
(6.104 kHz)
2
10
/F
CH
F
CH
/2
10
(12.21 kHz)
F
CH
: Oscillation frequency
Output frequency = F
CH
/2 10
= 12.5 MHz/1024
12.21 kHz