##General Information

Link to the official repository

###Objectives

• provide open-source(Lesser GPL3) usb host library for embedded devices
• execution speed. This library doesn't use blocking sleep, making low overhead on runtime performance
• use static allocation for all of its buffers. This means no allocation and reallocation is affecting performance (possibility of memory fragmentation. execution time indeterminism). No malloc(), realloc(), free()
• do not depend on any operating system

Supported hardware

• stm32f4discovery

Supported device drivers

• HUB
• Gamepad - XBox compatible Controller
• Generic Human Interface driver: mouse, keyboard (raw data)
• USB MIDI devices (raw data + note on/off)

Steps to compile library and demo

Prerequisities

Make sure the following prerequisities are installed to be able to compile this library

• git for libopencm3 submodule fetch
• gcc-arm-none-eabi toolchain for cross compilation
• cmake
• ccmake (optional)
• openocd (optional)

Basic setup

1. go to build directory located in the root of the project

cd build

2. compile demo and the library with the default options set

cmake .. && make

Executable demo is placed into build/demo.hex. Library is placed into build/src/libusbhost.a.

Advanced setup

cmake initial cache variables

Cache variable	Value	Description
USE_STM32F4_FS	TRUE	Enable STM32F4 Full Speed USB host peripheral
USE_STM32F4_HS	TRUE	Enable STM32F4 High Speed USB host peripheral
USE_USART_DEBUG	TRUE	Enable writing of the debug information to USART6
OOCD_INTERFACE	"stlink-v2"	Interface configuration file used by the openocd
OOCD_BOARD	"stm32f4discovery"	Board configuration file used by the openocd

You can alter these by issuing the following commands in the build directory

• Graphical user interface

ccmake ..

• Command line interface

cmake .. -D{VARIABLE}={VALUE}

Flashing

If the openocd is installed, make flash executed in the build directory flashes the build/demo.hex to the stm32f4discovery board.

Reading debug output

The following table represents the configuration of the debug output

GPIO	GPIOC6
USART periphery	USART6
Function	UART TX
Baud rate	921600
Uart mode	8N1

License

The libusbhost code is released under the terms of the GNU Lesser General Public License (LGPL), version 3 or later.

See COPYING.GPL3 and COPYING.LGPL3 for details.