MIKROE-798 mikroElektronika, MIKROE-798 Datasheet - Page 32

• Manufacturer Part Number: MIKROE-798
• Description: Development Boards & Kits - PIC / DSPIC EASYPIC v7 DEVELOPMENT SYSTEM
• Manufacturer: mikroElektronika

Specifications of MIKROE-798

• Rohs: yes
• Product: Development Boards
• Tool Is For Evaluation Of: PIC18F45K22
• Core: PIC
• Interface Type: RS-232, USB
• Operating Supply Voltage: 5 V
• Description/function: Development board only, touch screen, pencil, DS1820, LCD, serial cable, GLCD not included
• Dimensions: 266 mm x 220 mm

page 32
Freq = 3kHz, Duty Cycle = 50%
Freq = 3kHz, Duty Cycle = 80%
Freq = 3kHz, Duty Cycle = 20%
Figure 19-1: Piezo
buzzer connected to RE1
microcontroller pin
DATA BUS
PERSPECTIVE
PERSPECTIVE
PERSPECTIVE
Modulated) signal – a square wave signal, which is nothing more than
VIEW
VIEW
VIEW
VIEW
VIEW
VIEW
TOP
TOP
TOP
Microcontrollers can create sound by generating a PWM (Pulse Width
of J21 jumper. Buzzer is driven by transistor Q8 (Figure 19-1).
PZ1
PZ1
PZ1
Freq = 3kHz,
Volume = 50%
Freq = 3kHz,
Volume = 80%
Freq = 3kHz,
Volume = 20%
RE1 microcontroller pins, which is determined by the position
with piezo buzzer which can be connected either to RC2 or
VCC-5V
VCC-5V
VCC-5V
provided with analog electrical signal. EasyPIC
sizes, which can be used to create sound waves when
electric component that comes in different shapes and
Q8
BC846
Q8
BC846
Q8
BC846
generators, called piezo buzzers. Piezo buzzer is an
RE1
RC2
of piezo electricity is the production of sound
deform. One of the most widely used applications
piezoelectric material causes it to physically
Piezo Buzzer
pressure, but also providing the charge to the
Piezo electricity is the charge which accumulates
in certain solid materials in response to mechanical
R27
10K
R27
10K
R27
10K
J21
R3
1K
R3
1K
R3
1K
How to make it sing?
Buzzer starts "singing" when you provide
PWM signal from the microcontroller
to the buzzer driver. The pitch of the
sound is determined by the frequency,
and amplitude is determined by the
duty cycle of the PWM signal.
BUZZER
BUZZER
BUZZER
BUZZER
R27
10K
R3
1K
J21
J21
J21
VCC-5V
Q8
BC846
PZ1
BUZZER
™
v7 comes
PERSPECTIVE
RC2
RE1
RC2
RE1
RC2
RE1
VIEW
VIEW
TOP
a sequence of logic zeros and ones. Frequency of the square
signal determines the pitch of the generated sound, and duty
cycle of the signal can be used to increase or decrease the
volume in the range from 0% to 100% of the duty cycle. You
can generate PWM signal using hardware capture-compare
module, which is usually available in most microcontrollers,
or by writing a custom software which emulates the desired
signal waveform.
Supported sound frequencies
Piezo buzzer’s resonant frequency (where you can expect it's
best performance) is 3.8kHz, but you can also use it to create
sound in the range between 2kHz and 4kHz.
Enabling Piezo Buzzer
In order to use the on-board Piezo Buzzer in
your application, you first have to connect the
transistor driver of piezo buzzer to the appropriate
microcontroller pin. This is done using jumper J21.
You can place the jumper in two positions, thus
connecting the buzzer driver to either RE1 or RC2
microcontroller pin.
Figure 19-2:
Use jumper
J12 to
connect
Piezo buzzer
on RE1 or
RC2 pin