tinyusb

What Is tinyusb

tinyusb is an open-source (BSD-licensed) USB host/device/otg stack for embedded micro-controller. It is developed using Test-Driven Development (TDD) approach to eliminate bugs as soon as possible. TDD indeed works with C & embedded with the help of Ceedling, Unity & CMock as a testing framework.

More detail on TDD can be found at James W. Grenning's book "Test Driven Development for Embedded C" and throwtheswitch's Ceedling, CMock & Unity

Features

RTOS

tinyusb is designed to be OS-ware and run across OS vendors, thanks to its OS Abstraction Layer (OSAL). However, it can also run without an OS (OSAL will be expanded to be a state machine in this case). Currently the following OS can be run with tinyusb (out of the box).

• None OS
• FreeRTOS

Host

• HID Mouse
• HID Keyboard
• MSC coming soon...
• Hub coming soon...

Device

coming soon ...

Coding Standards

tinyusb make use of goodie features of C99, which saves a tons of code lines (also means save a tons of bugs). However, those features can be misused (plus C is a dangerous language by itself) and pave the way for bugs sneaking into. Therefore, to minimize bugs, the author try to comply with published Coding Standards like:

• MISRA-C
• Power of 10
• ...

MISRA-C 2004 Exceptions

MISRA-C is well respected & a bar for industrial coding standard. Where is possible, MISRA-C is followed but it is almost impossible to follow the standard without the following exceptions:

• Rule 2.2: use only /* It has long passed the day that C99 comment style // will cause any issues, especially compiler's C99 mode is required to build tinyusb. I think they will eventually drop this rule in upcoming MISRA-C 2012.
• Rule 8.5: No definitions of objects or function in a header file function definitions in header files are used to allow 'inlining'
• Rule 14.7: A function shall have a single point of exit at the end of the function Unfortunately, following this rule will have a lot of nesting if-else, I prefer to exit as soon as possible with assert style and flatten if-else.
• Rule 18.4: Unions shall not be used sorry MISRA, union is required to effectively mapped to MCU's registers
• expect to have more & more exceptions

Power of 10 Exceptions

• coming soon

Is It Ready

Although tinyusb is still under developing, but most of the code can run out of the box with supported boards

Getting Started

coming soon ...

Supported MCUs

• NXP LPC18xx/LPC43xx family

Supported Toolchains

currently only lpcxpresso/redsuite is supported. However Keil & IAR are always on top of the list.

Supported Boards

this codebase can run out of the box with the following boards

NXP LPC18xx/LPC43xx

• Embedded Artists LPC4357 OEM & Base board
• NGX Technologies LPC4330 Explorer

How Can I Help

If you find my little USB stack is useful, please take some time to file any issues that you encountered. It is not necessary to be a software bug, it can be a question, request, suggestion etc. We can consider each github's issue as a forum's topic. Alternately you can buy me a cup of coffee if you happens to be in Hochiminh city.

License

BSD license for most of the codebase, but each file is individually licensed especially those in /vendor folder. Please make sure you understand all the license term for files you use in your project.