barcode reader application in asp.net BOOTLOADER REQUIREMENTS in Software

Printer QR Code in Software BOOTLOADER REQUIREMENTS

BOOTLOADER REQUIREMENTS
Decode QR Code In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Creating QR Code In None
Using Barcode creator for Software Control to generate, create Denso QR Bar Code image in Software applications.
Just as the system needs to be able to communicate with the host, the host must be able to communicate with the system. Again, this is a system requirement, meaning that there must be hardware as well as software to take advantage of the bootloader functionality built into the system. With the trend toward simpler systems using PCs with more complex, proprietary, and licensed interfaces, this is becoming more and more of a problem. As will be shown later in this chapter, I will tend to stick with a simple RS-232-based (UART) bootloader using a basic terminal emulator program on my PC, but this is a slow method of passing new application code to the PIC microcontroller, and you might want to implement a USB-based bootloader, although the code is signi cantly more complex and will require a very good understanding of USB Windows device model programming as well as PC application programming. When you are rst starting out with a bootloader, use a simple interface (such as the RS-232 bootloader shown later in this chapter) and develop the right technology for your application from there. While MPLAB ICD capabilities are becoming more prevalent throughout the PIC microcontroller line card, there still are not that many part numbers that can write to their own program memory. This limits the devices that you can use in your application and makes it more dif cult to select the part number that is best for your application. Unfortunately, there isn t a search parameter on Microchip s Web site that allows you to get a fast list of PIC microcontrollers that would support bootloaders, so you will have to go through the list of part numbers that have the basic I/O features that you are looking for and then go through each datasheet doing a search on the EEPGM bit of EECON1 this bit is used to select between data EEPROM and Flash program memory for reading and burning in new values. There also should be an EEDATH register that is used for transferring the high byte s data to and from program memory Flash. When you create your bootloader code, it must be done with an eye toward not impeding execution of the actual application code. In the bootloader below I have moved as much of the code as possible to the top of the PIC microcontroller s memory and made sure that it does not overwrite the interrupt vector (address 0x0004). You also should keep MPLAB ICD in the back of your mind you might have an application in which the bootloader is going to be implemented in the eld, but you may want to use MPLAB ICD for debugging both the initial application code and the bootloader; to avoid any problems with MPLAB ICD, you should keep the last 256 addresses free. In some cases it will be impossible to avoid placing the bootloader over interrupts. A good example of this is a bootloader that uses the USB port built into the PIC microcontroller. In this case you will have to do two things. The rst is to ensure that there will be no application code addressed in this area, and the second is to write only applications that do not use interrupts. This does limit the applications somewhat, and you will have to decide whether or not the advantages make this course of action appropriate. Keeping assembly application code from being placed in this area is easy to do using the org directives. For compiled code, this will require modifying the device .lkr le; below I have listed the modi ed 18f4450i.lkr le that could be used for building an application that will be loaded by a bootloader.
QR-Code Decoder In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
QR Code ISO/IEC18004 Generation In Visual C#
Using Barcode drawer for .NET framework Control to generate, create Quick Response Code image in Visual Studio .NET applications.
Encode QR In Visual Studio .NET
Using Barcode generation for ASP.NET Control to generate, create QR image in ASP.NET applications.
Draw QR Code In .NET Framework
Using Barcode drawer for .NET Control to generate, create QR Code image in Visual Studio .NET applications.
Encoding QR In Visual Basic .NET
Using Barcode generation for Visual Studio .NET Control to generate, create Denso QR Bar Code image in VS .NET applications.
Make Barcode In None
Using Barcode generator for Software Control to generate, create bar code image in Software applications.
Generate Code 128 Code Set B In None
Using Barcode printer for Software Control to generate, create Code 128 Code Set B image in Software applications.
Creating UPC A In None
Using Barcode drawer for Software Control to generate, create Universal Product Code version A image in Software applications.
USS Code 39 Creation In None
Using Barcode creator for Software Control to generate, create Code 3/9 image in Software applications.
ECC200 Encoder In None
Using Barcode printer for Software Control to generate, create ECC200 image in Software applications.
Draw Leitcode In None
Using Barcode printer for Software Control to generate, create Leitcode image in Software applications.
Make Data Matrix In VS .NET
Using Barcode creation for Reporting Service Control to generate, create Data Matrix image in Reporting Service applications.
Draw Code 39 In C#
Using Barcode creation for .NET Control to generate, create Code 3/9 image in VS .NET applications.
Bar Code Recognizer In Visual Basic .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in VS .NET applications.
Drawing Code 128 In None
Using Barcode printer for Office Word Control to generate, create Code 128C image in Office Word applications.
Drawing Data Matrix ECC200 In VB.NET
Using Barcode creation for .NET framework Control to generate, create Data Matrix ECC200 image in .NET framework applications.
1D Barcode Encoder In Visual Basic .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Linear image in VS .NET applications.
Encode DataBar In Java
Using Barcode printer for Java Control to generate, create GS1 DataBar image in Java applications.
Copyright © OnBarcode.com . All rights reserved.