herunterladen
September 2012 Doc ID 022706 Rev 2 1/14
AN4041
Application note
APWLink+ microphone USB demonstration boards based on the
MP34DT01, MP45DT02, or MP34DB01
Introduction
The purpose of this application note is to give a brief description of the APWLink+
microphone USB demonstration boards from STMicroelectronics. These boards host the
microcontroller STM32F107RC and either the MP45DT02, MP34DT01 (top-port digital
microphones) or the MP34DB01 (bottom-port digital microphone). Figure 1 shows the
capability of the board to host these microphones.
These microphones are analog-to-digital transducers, in other words, they are able to sense
sound pressure and convert this signal to a digital signal using the pulse-density modulation
(PDM) technique. The STM32 microcontroller decodes the PDM signal coming from the
microphones and streams the audio via the USB.
This document will provide a brief description of the software that decodes the PDM signal
and also information about the hardware as well as simple steps to use the boards. Ordering
information for these boards can be found in Appendix C on page 12.
Figure 1. APWLink+ demonstration board
5PQ WJFX
#PUUPNWJFX
'VMMCPBSEWJFX
5PQWJFX
#PUUPNWJFX
.JDSPQIPOFTFDUJPO[PPNWJFX
.1%5
.1%5
.1%#
www.st.com
Verzeichnis
