We spoke with Michael Barr (@embeddedbarr) about the Barr Group embedded systems survey.
You can download the 2018 survey at the Barr Group survey page. The Barr Group Embedded C Coding Standardis also free to download (with registration). You can buy a paper copy on Amazon.
Programming Embedded Systems in C and C++ 1st Editionby Michael Barr, also available for free in HTML on the Barr Group site. The second edition is Programming Embedded Systems: With C and GNU Development Tools, 2nd Editionby Michael Barr and Anthony Massa.
The second book was Embedded Systems Dictionaryby Jack Ganssle and Michael Barr
Elecia’s book is Making Embedded Systems: Design Patterns for Great Software.