Addendum to Chapter 1 Notes

There are still a few things I needed to clear up for myself after the JTAG standard:

What does Board Bring-Up entail as a phase of development?: From Asset InterTech - Board bring-up is a phased process whereby an electronics system, inclusive of assembly, hardware, firmware, and software elements, is successively tested, validated and debugged, iteratively, in order to achieve readiness for manufacture.

What is an Exception or Interrupt Vector Table?: This is a data structure that associates interrupt-handling routines with a group of interrupt-requests in a table of interrupt vectors.  Each entry in the table is the address of an interrupt-handling routine.  This is structure is common throughout processor architectures, but it can also be implemented in different architecture-specific fashions.

What does the Stack do again?: In computer science, computer engineering and programming language implementations, a stack machine is a computer processor or a virtual machine in which the primary interaction is moving short-lived temporary values to and from a push down stack. In the case of a hardware processor, a hardware stack is used. The use of a stack significantly reduces the required number of processor registers. Stack machines extend push-down automata with additional load/store operations or multiple stacks and hence are Turing-complete.  Over the evolution of the computer and emergence of virtual stack machines there have been a wide array of implementations.  A somewhat recent example relevant to the study of embedded systems is the ZPU microprocessor stack machine.  It was designed Zylin AS to run supervisory code for FGPA systems. 

What is Turing-Completeness?: In computability theory, a system of data-manipulation rules (such as a model of computation, a computer's instruction set, a programming language, or a cellular automaton) is said to be Turing-complete or computationally universal if it can be used to simulate any Turing machine (devised by English mathematician and computer scientist Alan Turing). This means that this system is able to recognize or decide other data-manipulation rule sets. Turing completeness is used as a way to express the power of such a data-manipulation rule set. Virtually all programming languages today are Turing-complete.

What do we mean in Computer Science when we say Implicit or Explicit?: Something that is implicit is done for you behind-the-scenes, whereas something explicit is the manual approach to achieving a change we want by writing out the instructions to be done. 

And finally, What is Clock Stabilization?: Let's take the example of crystal oscillator used for clock timing, and an accompanying Oscillator Startup Timer (OST).  When a crystal oscillator starts up, the frequency of its pulse is not constant, and would cause the clock pulse to also be non-constant.  This would lead to timing errors, which would propagate into a slew of other problems.  The OST ensures that the system only operates when the oscillator produces a stable pulse.  It generally holds the system's reset for a set number of oscillator cycles to wait for a stable pulse.