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"
- 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
- Mass-Storage (MSC) coming soon...
- Hub coming soon...
- Multiple host controllers
Device
coming soon ...
Coding Standards
tinyusb make use of goodies 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 in early stage of 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 code base can run out of the box with the following boards
NXP LPC18xx/LPC43xx
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. Alternatively, you can buy me a cup of coffee if you happen to be in Hochiminh city.
License
BSD license for most of the code base, 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.