read barcode in asp net web application HARDWARE INTERRUPTS in Software

Painting QR Code ISO/IEC18004 in Software HARDWARE INTERRUPTS

HARDWARE INTERRUPTS
Decoding QR Code ISO/IEC18004 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Quick Response Code Drawer In None
Using Barcode generator for Software Control to generate, create QR image in Software applications.
Properly used, hardware interrupts can greatly improve the ef ciency of your applications as well as simplify your application code. Despite these potential advantages, they are seldom used and often avoided as much as possible. For many application developers, interrupts are perceived as being dif cult to work with and something that complicates the application code and its execution. This perception isn t accurate if you follow the basic rules that will be discussed in this book. Hardware interrupts in computer systems are analogous to interrupts in your everyday life. As the computer processor is executing application code, a hardware event may occur that will request the processor to stop executing and respond to or handle the hardware event. Once the processor has responded to the event, the regular program execution can continue where it was stopped. The hardware event requesting the interrupt can be a timer over ow, a serial character received (or nished sending), a user pressing a button, and so on. There are many different hardware events that will cause an interrupt to take place similar to you getting a phone call or other distraction while working. Like a phone call giving you new information, the application code often uses the information provided by the interrupt as new data to consider during execution. Possible hardware interrupt requests that you will have to consider responding to in your microcontroller applications include such situations as changing digital inputs, the completion of an analog-to-digital conversion, the receipt of a serial character, and so
Decoding QR Code ISO/IEC18004 In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Encoding Denso QR Bar Code In C#
Using Barcode drawer for .NET Control to generate, create QR Code image in VS .NET applications.
EMBEDDED MICROCONTROLLERS
Drawing QR In VS .NET
Using Barcode generator for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
QR Code JIS X 0510 Creator In Visual Studio .NET
Using Barcode generation for .NET Control to generate, create Quick Response Code image in Visual Studio .NET applications.
4 Interrupt Handler Execution Execution Jump to Interrupt 3 Handler 5
QR Code 2d Barcode Creation In VB.NET
Using Barcode maker for .NET framework Control to generate, create Denso QR Bar Code image in Visual Studio .NET applications.
Print Code 39 In None
Using Barcode encoder for Software Control to generate, create Code 39 Extended image in Software applications.
Execution Mainline Return 6 5 Mainline Code Execution Resume
Printing EAN-13 In None
Using Barcode creator for Software Control to generate, create European Article Number 13 image in Software applications.
Generate Data Matrix 2d Barcode In None
Using Barcode generator for Software Control to generate, create ECC200 image in Software applications.
1 Mainline Code Execution 2
Make Barcode In None
Using Barcode generation for Software Control to generate, create bar code image in Software applications.
Print Barcode In None
Using Barcode creator for Software Control to generate, create bar code image in Software applications.
Hardware Interrupt Request Received
GS1 - 12 Generation In None
Using Barcode creation for Software Control to generate, create UPC - E0 image in Software applications.
Code 128 Code Set C Generation In Visual Studio .NET
Using Barcode generation for Reporting Service Control to generate, create Code128 image in Reporting Service applications.
Figure 1.8 The steps taken when a hardware event requests that the execution of the application is interrupted to respond to it.
Code 39 Full ASCII Drawer In None
Using Barcode generation for Office Excel Control to generate, create Code 39 image in Office Excel applications.
UCC-128 Maker In C#.NET
Using Barcode drawer for .NET Control to generate, create USS-128 image in .NET framework applications.
on. When sending a string of data, you may use interrupts to load in the next bit or byte to be output without affecting the primary application s execution. In any case, it is important to quickly respond to these requests and store the new information as quickly as possible to avoid negatively affecting how the application runs. A good rule of thumb is to code your applications so the data provided by hardware interrupts is in as simple a form as possible and reading it is as simple as reading a byte or a bit. The process of responding to a hardware interrupt request follows the six distinct steps outlined in Fig. 1.8. If a hardware interrupt request is received while the primary application (or mainline) code is executing (1 in Fig. 1.8), the processor continues executing the current instruction and then tests to see if interrupt requests are allowed. Hardware interrupt requests do not have to be responded to immediately or at all. This is an important point because an application may ignore interrupt requests if time sensitive or high priority code is being executed. If the request is ignored, the hardware will continue requesting until the application code enables the processor circuitry that responds to interrupts. This is analogous to you ignoring a phone call and listening to a message later because you were doing something that you considered more important. If the processor can respond to a hardware interrupt request, execution of the mainline code is stopped (2 in Fig. 1.8) and the current program counter and other important data is saved until the interrupt response has completed and execution returns to where it was stopped. The important data is often called the context data or context information, and consists of the contents of the registers that were being used by the mainline code when it was interrupted. This context information may be saved automatically by the processor or require special code to save and retrieve it. The PIC microcontroller requires special code to save and retrieve the context data. With the return address saved, the processor then changes the program counter to the interrupt handler vector (3 in Fig. 1.8). The interrupt handler (4 in Fig. 1.8) is the subroutine-like code that processes the data from the interrupting hardware and stores it for later use. You may see terms like interrupt service routine in some references instead of interrupt handler, but they both mean the same thing.
GTIN - 13 Creation In VS .NET
Using Barcode generation for Reporting Service Control to generate, create GS1 - 13 image in Reporting Service applications.
Code39 Generator In Java
Using Barcode creation for Java Control to generate, create Code 3/9 image in Java applications.
Code 128C Generator In .NET Framework
Using Barcode printer for .NET framework Control to generate, create Code 128 Code Set A image in VS .NET applications.
Encoding EAN / UCC - 13 In Objective-C
Using Barcode encoder for iPad Control to generate, create EAN128 image in iPad applications.
Copyright © OnBarcode.com . All rights reserved.