User Manual

P A G E 22
F u s i o n f o r A R M v 8 M a n u a l
C O M M U N I C A T I O N
Communication
Communication connectors allow the development board to be connected with many
different devices that use high-layer communication protocols such as Ethernet,
USB, etc. Also, there is a USB-UART converter, offering simplified communication with
the personal computer over the emulated serial interface. Each of these connectors
will be described in more details, in the following sections of the manual.
USB-UART
UART (Universal Asynchronous Receiver/Transmitter) interface is one of the most
common interfaces for data exchange between the MCU and other external devices.
Fusion for ARM v8 development board offers the UART connectivity over the USB-C
connector (1) by utilizing the FT230XQ, a popular USB-UART bridge IC, produced
by FTDI Chip. This IC contains the complete USB stack necessary for the interface
bridging between the UART peripheral of the MCU and the USB interface of the PC.
FT230XQ drivers are available for download from the Fusion for ARM v8 product web
page, as well as from the official FTDI drivers download web page.
To enable data exchange via the USB-UART connector, the MCU UART peripheral lines
must be connected to the corresponding pins of the FT230XQ IC. This can be done
using the four-pole DIP switch, labeled as USB/UART (SW1 on the schematic). Only
two switch positions are used for the UART setup, while the other two switch positions
are reserved for USB HOST/DEVICE functions:
SW1.3 ON (up): connects the UART RX pin from the MCU to the FT230XQ IC;
OFF (down): disconnects the UART RX pin from the FT230XQ IC
SW1.4 ON (up): connects the UART TX pin from the MCU to the FT230XQ IC;
OFF (down): disconnects the UART TX pin from the FT230XQ IC
The USB mode selection is done using an a specialized controller IC solution. This IC
provides Configuration Channel (CC) control logic detection and indication functions.
The HOST/DEVICE detection pin (USB ID), as well as the HOST/DEVICE configuration
pin (USB PSW) of the MCU, can be connected with the logic control circuit by using the
DIP switch (SW1), located in the BOARD SETUP section:
SW1.1 ON (up): connects the HOST/DEVICE configuration pin of the MCU with the
PTN5150 logic control circuit;
OFF (down): disconnects the HOST/DEVICE configuration pin from the
PTN5150 logic control circuit
SW1.2 ON (up): connects the HOST/DEVICE detection pin of the MCU with the logic
control circuit;
OFF (down): disconnects the HOST/DEVICE detection pin from the logic
control circuit
To set up Fusion for ARM v8 development board as the USB HOST, the PSW pin
should be set to a LOW logic level (0) by the MCU. If set to a HIGH logic level (1) the
development board acts as a DEVICE. In HOST mode, Fusion for ARM v8 development
board provides the power over the USB-C connector for the attached device.
The USB ID pin is used to detect the type of the device attached to the USB port,
according to USB OTG specifications: the USB ID pin connected to GND indicates a
HOST, while the USB ID pin set to a high impedance state (HI-Z) indicates that the
connected peripheral is a DEVICE.
USB
USB (Universal Serial Bus) (2) is a very popular industry standard that defines cables,
connectors, and protocols used for communication and power supply between
devices. USB-C (USB Type-C connector) is the latest version of the USB connector,
developed by the USB Implementation Forum (USB-IF). Due to its many advantages
including symmetrical pinout, higher current capacity, and faster supported data
rates, it is probably going to replace all the previous USB connector types. USB-C
connector supports both USB HOST and USB DEVICE modes. This enables MCUs
equipped with the USB peripheral to act either as a USB HOST or as a USB DEVICE,
allowing development of a range of various USB based applications.