Digital Control Engineering book recommendations
Sad about the down-votes, people should be encouraged to seek enlightenment - however you should show what attempts/similar textbooks you've seen/looked for already.

During my robotics engineering degree, I used the following textbooks and I recommend them:

Contro Systems Engineering by Nise, for mostly Classical control (not quite digital, but very important to understand first)

Robot Modelling and Control by Spong et al. 
This one is very good for modern control theory with digital systems, and state-space feedback which is the next step up from classical PID style control. Pretty sure it also has Riccatti style Linear Quadratic Regulator control (LQR) in there. 

You may want to find a more practical 'hands on' control theory textbook that actually implements fully, with ARM Cortex processors and C code examples, the control theory shown in the usual textbooks. You may find it a bit ambiguous as to the step to take a nice control gain matrix and actually make it into a workable program running on an embedded system. 

I know that Texas Instruments have some ARM Cortex dev boards as platforms used by at least one textbook with fully worked examples for control, including the use of real-time operating system kernels.