User Manual

5. Connectivity
mikromedia 3 includes support for USB(HOST/DEVICE).
Besides that, it also offers two 1x26 pin headers, which are
used to directly access the MCU pins.
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Figure 11: USB-C connector view
5.1 USB
The host MCU is equipped with the USB peripheral module, allowing
simple USB connectivity. USB (Universal Serial Bus) is a very popular
industry standard that defines cables, connectors, and protocols used
for communication and power supply between computers and other
devices. mikromedia 3 supports USB as HOST/DEVICE modes, allowing
the development of a wide range of various USB-based applications. It
is equipped with the USB-C connector, which offers many advantages,
compared to earlier types of USB connectors (symmetrical design, higher
current rating, compact size, etc).
The USB mode selection is done using a monolithic controller IC. This IC
provides Configuration Channel (CC) detection and indication functions.
To set up mikromedia 3 as the USB HOST, the USB_PSW pin should be set
to a LOW logic level (0) by the MCU. If set to a HIGH logic level (1), mikromedia 3
acts as a DEVICE. While in HOST mode, mikromedia 3 provides power over
the USB-C connector (1) for the attached DEVICE. The USB_PSW pin is
driven by the host MCU, allowing the software to control the USB mode.
The USB ID pin is used to detect the type of the device attached to the USB
port, according to the USB OTG specifications: the USB ID pin connected to
GND indicates a HOST device, while the USB ID pin set to a high impedance
state (HI-Z) indicates that the connected peripheral is a DEVICE.
N O T EWhen mikromedia 3 is working in USB HOST mode, it must not be
mounted to another USB HOST (such as PC).
mikromedia 3 for STM32 CAPACITIVE U S E R M A N U A L
CONNECTIVITY
P A G E 19