barcode reader application in asp.net PIC Micro in Software

Maker QR Code in Software PIC Micro

PIC Micro
Quick Response Code Reader In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code Maker In None
Using Barcode drawer for Software Control to generate, create QR Code ISO/IEC18004 image in Software applications.
100 K Momentary Closed Button 10 K
Denso QR Bar Code Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Generate QR In C#
Using Barcode printer for .NET Control to generate, create QR Code image in VS .NET applications.
I/O Device
QR Code ISO/IEC18004 Generator In VS .NET
Using Barcode encoder for ASP.NET Control to generate, create QR Code 2d barcode image in ASP.NET applications.
Quick Response Code Generation In VS .NET
Using Barcode generator for VS .NET Control to generate, create QR-Code image in .NET applications.
Data I/O
QR Code Drawer In Visual Basic .NET
Using Barcode creation for .NET Control to generate, create Quick Response Code image in Visual Studio .NET applications.
GTIN - 128 Maker In None
Using Barcode encoder for Software Control to generate, create EAN 128 image in Software applications.
Figure 15.9 A digital interface line can be shared with a simple button input that has high-impedance pull-ups and pull-downs.
Draw Data Matrix 2d Barcode In None
Using Barcode generator for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Code 3 Of 9 Generation In None
Using Barcode maker for Software Control to generate, create Code 39 Extended image in Software applications.
INTERFACING TO EXTERNAL DEVICES
Painting UPC A In None
Using Barcode generator for Software Control to generate, create UPC Code image in Software applications.
Draw Bar Code In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
the current ow between Vcc and ground. If the PIC microcontroller is going to read the button high (switch open) or low (switch closed), it will be driven on the bus at low currents when the pin is in input mode. If the button switch is open, then the 100-k resistor acts like a pull-up, and a 1 is returned. When the button switch is closed, then there will be approximately 1/2 V across the 10-k resistor, which will be read as a 0. The button with the two resistors pulling up and down are like a low-current driver, and the voltage produced by them is easily overpowered by active drivers. As with the rst method, the external input device cannot receive data except when the PIC microcontroller is driving the circuit. A separate clock or enable should be used to ensure that input data is received when the PIC microcontroller is driving the line. Two points about this method: The second approach can be extrapolated to work with a switch matrix keyboard. This can become very complex, but it will work. Second, a resistor-capacitor network for debouncing the button cannot be used with this circuit because a resistor-capacitor network will slow down the response of the PIC microcontroller driving the data input pin and cause problems with the correct value being accepted. When a button is shared with an input device; such as is shown in Fig. 15.9, software button debouncing will have to be done inside the PIC microcontroller.
Making Leitcode In None
Using Barcode generation for Software Control to generate, create Leitcode image in Software applications.
Scanning UPC Code In Visual C#.NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
SIMULATED OPEN-COLLECTOR/OPEN-DRAIN I/O
Bar Code Printer In None
Using Barcode encoder for Microsoft Word Control to generate, create barcode image in Word applications.
Scan Data Matrix 2d Barcode In C#
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
Open-collector/open-drain outputs are useful in several different interfacing situations. Along with providing a node in a dotted AND bus, they are also useful to interface with I2C and other networks. I nd the single-open drain pin available in the different PIC microcontroller devices to be insuf cient for many applications, which is why I nd it useful to simulate an open-drain driver with a standard I/O pin. An open-drain pin (shown in Fig. 15.10) consists of a N-channel MOSFET transistor with its source connected to the I/O pin. Because there is no P-channel high driver in the pin circuit, when a 1 is being output, the only transistor will be turned off, and
UCC.EAN - 128 Creator In VS .NET
Using Barcode encoder for VS .NET Control to generate, create GTIN - 128 image in Visual Studio .NET applications.
Make Data Matrix ECC200 In Java
Using Barcode creator for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
Ctrl_Write
Recognize Data Matrix In Visual Basic .NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
Printing Code128 In .NET Framework
Using Barcode creator for VS .NET Control to generate, create Code 128 image in .NET framework applications.
TRIS Q Register
Data Bus
Pin_Write
PORT Register
Pin_Read
Figure 15.10 The open-drain I/O pin in the PIC microcontroller allows multiple drivers to share a single bus.
PIC MICROCONTROLLER APPLICATION DESIGN AND HARDWARE INTERFACING
the pin is allowed to oat. Floating generally is referred to as the case in which a pin is left unconnected; when used in this situation, the pin is at the voltage level of the rest of the net unless it is driving the net low. When the data out bit is low (and TRIS is enabled for output), the pin is pulled low. Otherwise, it is not electrically connected to anything or tristated. This action can be simulated by using the code listed below that enables the I/O pin output as low if the carry ag is reset. If the carry ag is set, then the pin is put into input mode.
bcf bsf btfss goto nop bsf goto bcf goto bcf PORT#, pin STATUS, RPO STATUS, C $ + 4 TRIS ^ 0x080, pin $ + 3 TRIS ^ 0x080, pin $ + 1 STATUS, RPO ; ; ; ; Make Sure PORTB Pin Bit is 0 If Carry Set, Disable Open Collector Carry Reset, Enable Open Collector
This code, which is designed for mid-range PIC microcontrollers, will either set the pin to input (tristate) mode or be pulled low on the sixth cycle after it has been invoked. I normally put this code into a macro, with the port and pin speci ed as parameters. It will seem like I went to some lengths to ensure that the timing was the same for making the bit tristate (input mode) or pulled low to 0, as well as the state speci ed by the carry ag. Regardless of the execution path, this code will take eight instruction cycles, and the I/O pin value will be changed at ve cycles. I did this because this function is often used with I2C or other network protocols, and using the carry ag allows bits to be shifted through the code easily. In the sample open-drain simulation code above, I reset the speci ed pin before potentially changing its TRIS value. This is to prevent it from being the wrong value based on reads and writes of other I/O pins.
Copyright © OnBarcode.com . All rights reserved.