use barcode reader in asp.net Vcc 10 K To Pin 3 (Contrast Voltage) of LCD in Software

Creator Denso QR Bar Code in Software Vcc 10 K To Pin 3 (Contrast Voltage) of LCD

Vcc 10 K To Pin 3 (Contrast Voltage) of LCD
Recognizing QR Code JIS X 0510 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code JIS X 0510 Generator In None
Using Barcode encoder for Software Control to generate, create QR Code JIS X 0510 image in Software applications.
Figure 17.15 Contrast control can be provided by a pot wired as a voltage divider.
Scanning QR In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Making QR Code JIS X 0510 In Visual C#
Using Barcode creation for .NET framework Control to generate, create QR Code image in .NET applications.
PIC MCU INPUT AND OUTPUT DEVICE INTERFACING
QR Generator In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
QR Code Creation In Visual Studio .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create QR Code image in VS .NET applications.
Vcc 74LS174
QR Code 2d Barcode Creation In VB.NET
Using Barcode maker for Visual Studio .NET Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
Making DataMatrix In None
Using Barcode maker for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
16 - Vcc
Code-128 Creation In None
Using Barcode generator for Software Control to generate, create Code 128B image in Software applications.
Generate UCC.EAN - 128 In None
Using Barcode generation for Software Control to generate, create UCC-128 image in Software applications.
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Draw Barcode In None
Using Barcode creator for Software Control to generate, create barcode image in Software applications.
Code-39 Generation In None
Using Barcode maker for Software Control to generate, create Code39 image in Software applications.
Gnd Vcc Con RS RW E D0 D1 D2 D3 D4 D5 D6 D7
UPC-E Supplement 5 Maker In None
Using Barcode maker for Software Control to generate, create Universal Product Code version E image in Software applications.
GTIN - 12 Creation In None
Using Barcode drawer for Excel Control to generate, create UPC-A Supplement 2 image in Microsoft Excel applications.
0.1 uF Vcc
Barcode Creation In .NET
Using Barcode generation for ASP.NET Control to generate, create bar code image in ASP.NET applications.
Print EAN / UCC - 13 In Java
Using Barcode generator for Eclipse BIRT Control to generate, create EAN 13 image in BIRT reports applications.
10 K
Draw UPC-A Supplement 2 In Java
Using Barcode generator for Java Control to generate, create Universal Product Code version A image in Java applications.
Encoding GS1 - 13 In Objective-C
Using Barcode generation for iPad Control to generate, create European Article Number 13 image in iPad applications.
1 - _Clr
2D Barcode Generation In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create Matrix 2D Barcode image in ASP.NET applications.
UPC-A Maker In Java
Using Barcode drawer for Java Control to generate, create Universal Product Code version A image in Java applications.
Clock Data
9 - Clk 3 - 1D
8 - Gnd
1Q - 2 2D - 4 2Q - 5 3D - 6 3Q - 7 4D - 11 4Q - 10 5D - 13 5Q - 12 6D - 14 6Q - 15 1K 1N914
Figure 17.16 two wires.
With this circuit, you can control an LCD with just
TWO-WIRE LCD CONTROL
There are a number of different ways to wire up an LCD. Earlier I noted that the 44780 could interface with 4 or 8 bits. To simplify the demands of microcontrollers, a shift register is often used to reduce the number of I/O pins to three. This can be further reduced by using the circuit shown in Fig. 17.16, in which the serial data is combined with the contents of the shift register to produce the E strobe at the appropriate interval. This circuit ANDs (using the 1-k resistor and IN914 diode) the output of the sixth D ip- op of the 74LS174 and the data bit from the device writing to the LCD to form the E strobe. This method requires one less pin than the three-wire interface and a few more instructions of code. I normally use a 74LS174 wired as a shift register (as shown in the schematic diagram) instead of a serial-in/parallel-out shift register. This circuit should work without any problems with a dedicated serial-in/parallel-out shift register chip, but the timings/clock polarities may be different. When the 74LS174 is used, note that the data is latched on the rising edge (from logic low to high) of the clock signal. Figure 17.17 is a timing diagram for the two-wire interface and shows the 74LS174 being cleared, loaded, and then the E strobe when the data is valid and 6Q and incoming data are high. In the diagram to the right I have shown how the shift register is written to for this circuit to work. Before data can be written to it, loading every latch with zeros clears the shift register. Next, a 1 (to provide the E gate) is written, followed by the R/S bit and the 4 data bits. Once the latch is loaded correctly, the data line is pulsed to strobe the E bit. The biggest difference between the three-wire and the two-wire
LCDs
Data
RS 4Qi 3Qi 2Qi 1Qi
Clock 1Q
RS 4Qi 3Qi 2Qi 1Qi
RS 4Qi 3Qi 2Qi
2Qo 1Qo
RS 4Qi 3Qi
3Qo 2Qo 1Qo
RS 4Qi
4Qo 3Qo 2Qo 1Qo
5Qo 4Qo 3Qo 2Qo 1Qo
74LS174 Clear 74LS174 Load
Figure 17.17 The synchronous serial waveform of the data coming in showing the bits propagating through the shift register.
interface is that the shift register has to be cleared before it can be loaded, and the two-wire operation requires more than twice the number of clock cycles to load 4 bits into the LCD. I ve used this circuit with the PIC microcontroller, BASIC Stamp, 8051, and AVR, and it really makes the wiring of an LCD to a microcontroller very simple. A signi cant advantage of using a shift register, as in the two circuits shown here, is the lack of timing sensitivity that will be encountered. The biggest issue to watch for is to make sure that the E strobe s timing is within speci cation (i.e., greater than 450 ns); the shift register loads can be interrupted without affecting the actual write. This circuit will not work with open-drain-only outputs (something that catches up many people). One note about the LCD s E strobe is that in some documentation it is speci ed as high level active, whereas in others it is speci ed as falling-edge-active. It seems to be falling-edge-active, which is why the two-wire LCD interface presented below works even if the line ends up being high at the end of data being shifted in. If the falling edge is used (as in the two-wire interface), then make sure that before the E line is output on 0, there is at least a 450-ns delay with no lines changing state. The following C routine could be used to write to the two-wire LCD interface:
LCDNybble(char Nybble, char RS) { int i;
Copyright © OnBarcode.com . All rights reserved.