In this appendix, we would like to bring you more general information about interfacing your Beagle hardware with more complicated devices, such as GPS receivers, wireless modules, or perhaps your own microcontroller-driven design for some special purpose. When interfacing other self-operating devices, there are a few industry standards which we will talk about in detail. An introduction to advanced embedded-device-debugging techniques will also be presented, and we will talk about the security issues in the current protocol implementation and how to increase the security by using data encryption. After reading you will have:
A general knowledge of the I2C and SPI buses
An understanding of what is needed for the Linux kernel, or ARM processor debugging
Implemented an encrypted data transfer between our client and server
In the last section of this appendix, you will also find the complete mapping of headers P8 and P9. This can serve as a handy reference to find out which pins are usable for you, and where to find the desired functionality.