User Manual

P A G E 24
mikromedia 4 for STM32 CAPACITIVE U S E R M A N U A L
P A G E 24
mikromedia 4
for STM32 CAPACITIVE
U S E R M A N U A L
6. Sound-related peripherals
By offering a pair of sound-related peripherals, mikromedia 4
rounds-up its multimedia concept. It features a piezo-buzzer,
which is extremely easy to program but can produce only the
simplest sounds, useful only for alarms or notifications.
The second audio option is the powerful VS1053B IC (1). It is
an Ogg Vorbis/MP3/AAC/WMA/FLAC/WAV/MIDI audio decoder,
and a PCM/IMA ADPCM/Ogg Vorbis encoder, both on a single
chip. It features a powerful DSP core, high-quality A/D and
D/A converters, stereo headphones driver capable of driving
a 30Ω load, zero-cross detection with the smooth volume
change, bass and treble controls, and much more.
6.1 Piezo buzzer
A piezo buzzer (2) is a simple device capable of reproducing sound. It
is driven by a small pre-biased transistor. The buzzer can be driven by
applying a PWM signal from the MCU at the base of the transistor: the
pitch of the sound depends on the frequency of the PWM signal, while the
volume can be controlled by changing its duty cycle. Since it is very easy to
program, it can be very useful for simple alarms, notifications, and other
types of simple sound signalization.
P A G E 24
AUDIO
2
Figure 14: mikromedia 4 back view
mikromedia 4 for STM32 CAPACITIVE U S E R M A N U A L