6. Data types
Each data object has a type associated with it. The type defines the set of values that the object can have and the set of...
5. Data Objects: Signals, Variables and Constants
A data object is created by an object declaration and has a value and type associated with it. An object can be a Constant, Variable,...
4. Lexical Elements of VHDL
Identifiers Identifiers are user-defined words used to name objects in VHDL models. We have seen examples of identifiers for input and output signals as well...
3. Basic Structure of a VHDL file
A digital system in VHDL consists of a design entity that can contain other entities that are then considered components of the top-level entity. Each...
2. Levels of representation and abstraction
2. Levels of representation and abstraction A digital system can be represented at different levels of abstraction [1]. This keeps the description and design...
1. Introduction VHDL
VHDL stands for VHSIC (Very High Speed Integrated Circuits) Hardware Description Language. In the mid-1980’s the U.S. Department of Defense and the IEEE sponsored the...
Graphics with Direct Memory Access
Drawing pictures on the screen using the bios interrupts is all very easy, but when push comes to shove, its also very, very slow as...
Some Basic Graphics
Switching Screen Modes The interrupt used for switching between screen modes, and for all graphics work is interrupt 10h. Subfunction 0 of this interrupt sets...
Mathematical Operators
Increment and Decrement These are two of the most basic and useful instructions in the instruction set. The instruction “inc” adds one to the parameter,...
Variables and Strings
In this the fourth tutorial we will cover how do allocate space in memory for variables in out programs and also how output messages on...
Active Components
All About Transistors: FET’s
It may seem hard to believe, but it was not too long ago that bipolar transistors began to replace vacuum tubes in mainstream electronics design....
Working with MosFet’s
The Metal-Oxide-Semiconductor Field-Effect Transistor, or MOSFET for short, is similar in many ways to the junction FET (JFET). Both are voltage-driven unipolar devices that depend...
Field Effect Transistors
Field Effect Transistors (FET’s): Field Effect Transistors (FET’s) are unipolar rather than bipolar devices, and this gives them certain properties that are superior to those...
Transistor Amplifier Design
We were having trouble finding an exact replacement transistor while repairing a piece of equipment. Figuring that an exact replacement was going to be impossible...
Pasive Components
Resistors
What do resistors do? Resistors limit current. In a typical application, a resistor is connected in series with an LED: Enough current flows to make...
Voltage Rating of a Capacitor
All capacitors have a maximum voltage rating and when selecting a capacitor consideration must be given to the amount of voltage to be applied across...
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