The following products, which range from training kits and videos to PDFs and source code, are available for free download.
Embedded C Coding Standard 
Barr Group's Embedded C Coding Standard was developed from the ground up to minimize bugs in firmware, by focusing on practical rules that keep bugs out while also improving the maintainability and portability of embedded software. The book (which is available in print, PDF, and HTML formats) details a set of guiding principles as well as specific rules for the use of data types, functions, preprocessor macros, variables, and much more.
Report: Embedded Systems Safety & Security Survey
Barr Group's Embedded Systems Safety & Security Survey is an annual worldwide survey of embedded systems designers that focuses specifically on their concerns and practices in relation to the safety and security of their current designs. Prior year results of these surveys are available for PDF download by interested parties in the embedded systems industry.
CRC Implementation Code in C
To save yourself time as well as to ensure your implementation of the CRC's modulo-2 arithmetic is efficient and bug-free, download Michael Barr's public domain CRC functions for embedded C/C++ programs. This small C source code library is available as a free digital download from our website and has been widely tested and deployed by thousands of embedded software developers.
Fast Accurate Memory Test Code in C
To save time and ensure that the memory chips in your systems are functioning correctly, download our fast, accurate memory test code library. This small C source code library is available as a free digital download from our website and has been widely tested and deployed by thousands of embedded software developers.