lcd module rcf8574 manufacturer

A regular LCD requires a lot of wires (parallel interface) to be connected with a Microcontroller.The Serial LCD  backpack built on PCF8574 IC uses the I2C bus to convert  the parallel interface to a serial one.This needs only2 wires SDA & SCL , apart from the power connections.

The blue preset is to adjust the contrast of the LCD. The black jumper on the left is to enable the Backlight of LCD. The I2C device has a HEX address by which a microcontroller can communicate with it.This is set by the 3 bits A0,A1 ,A2 .If no jumper is present , it is HIGH &  a jumper means LOW. By default all the 3 jumpers are open . ie., A0,A1 A2 all are 1s.

lcd.setBacklightPin(HIGH);  makes the P3 pin go High, which turns on the NPN transistor.This provides GND to the LED pin of LCD As the other LED pin is already connected to Vcc through the jumper , the LCD backlight glows.

This LCD I2C interface adapter can be added to a 16 x 2 or 20 x 4 character LCD display with a standard parallel interface to make it I2C compatible.  It can also be repurposed for other I2C to parallel tasks.

By default, the industry standard HD44780 compatible 16 x 2 and 20 x 4 character LCD displays require 4 or 8 parallel data lines to drive them along with a couple of pins for chip select and chip enable.  This consumes a lot of pins on the MCU.  This adapter board reduces the data pin requirements to only 2 pins which can also be shared with other I2C devices.

The backlight can be controlled ON/OFF, but the intensity is not directly controllable though the I2C interface.  Some modules have a jumper on the board that supplies Vcc power to the backlight.  That jumper can be removed and a voltage applied to the header pin nearest the ‘LED’ markings on the board to provide power to the backlight separately.  Note:  Some modules do not have this header / jumper installed, instead the solder pads have a trace connecting them.  It is possible to cut the trace between the pads and add header pins if desired.

The PCF8574 is a generic I2C to 8-bit I/O device and the module can be repurposed for other uses besides driving LCD modules.  Max I2C clock frequency is 100kHz which makes it most suited to lower speed applications.

VCC =  Connect to 5V.  This can come from the MCU or be a separate power supply.  Some LCD may operate at 3.3V and this module can also operate at 3.3V

The pin-out of the header which is soldered to the LCD follows for reference, but in general you don’t need to worry about it as the I2C interface board and software library takes care of this interface unless you are adapting the module for another use.  These pins are listed starting at the I2C header end of the board.

To use the adapter with an LCD, you will need to insert the 16-pin header into the 16 solder pad holes on the back of the LCD and solder them in place on the front side.  The pins are long and can be cut off before or after soldering.

Soldering the module on is easy to do, but if you already have other pins in those holes, they will need to be removed first before this board can be added.  The picture below shows the adapter mounted to the back of an LCD2004 4 x 20 character LCD.

This is the same module used on our I2C compatible LCD displays we sell and is well supported using the LiquidCrystal_I2C.h and similar libraries.  For using the board with software, you can check out one of the LCDs below that already have this module installed.

The PCF8574 itself is a general purpose 8-bit I/O expander for the I2C bus.  The reverse engineered schematics are provided here mainly for those who may want to adapt the module to other applications.  The I2C bus on this module is limited to a 100kHz clock frequency.

I2C Adapter Board fits right on the back of standard LC character display modules with 1 x Hitachi HD44780 or compatible display controller. The on-board PCF8574 or PCF8574A 8-bit I/O expander encodes the signals for the 4 data bits, the read/write select, register select, the enable signal, and the backlight-ON signal.

LCD character modules are “characteristically” simple display devices known for their very low power consumption, low cost and long-term reliability. They are designed to display alpha-numeric characters in preset patterns and do not have much. In most cases, they are small displays with only 8 or 16 or 32 characters, utilized for status reports and simple communication. It is the most popular display for hobbyist because of its ease of operation.

Orient Display offers many standard sizes including (characters x lines) 8×1, 8×2, 16×2, 16×4 , 20×2, 20×4 , 24×4, 40×4, and many more. Orient Display’s character LCD displays cover small LCD character display modules for tiny devices to large character LCD displays for medical equipments.

Orient Display character LCD modules use industrial standard Hitachi HD44780 controller or compatible controllers such as Sitronix ST7066U, Samsung S6A0069, so they can be quickly integrated into a new product or used as a replacement in your existing products.

The LCD panel technologies include TN, STN, FSTN, FFSTN or VA (Vertical Alignment) types and also with positive mode and negative mode and options of reflective, transflective or transmissive polarizers. There are different LED backlights available in various colors including yellow-green, white, red, blue, green, amber, and RGB LEDs as well as no backlight option.

The viewing angles for these character LCD displays are available with 6:00, 12:00, 3:00, and 9:00. Orient Display offers various IC options of character fonts including English/Japanese, western European, eastern European, Scandinavian European, Cyrillic (Russian), and Hebrew/Arabic. These LCD character modules and LCD modules can be used on industrial and consumer’s applications including printers, microwaves, water machines, medical devices, car and home audio, white goods, game machines, toys, industrial meters, etc.

Please see our character LCD display list here. If you can’t find any in the list, please check with our engineers to search our factory database or have a custom-made option.

I2C Interface Board is basically an IO expander board that helps minimize microcontroller / Arduino IO usage pin count. With this module, attached to the back of an character LCD Module, you can use only two pins (SDA and SCL) to the LCD modules.

The next step is to download and install the Arduino I2C LCD library for use with the backpack. First of all, rename the "LiquidCrystal" library folder in your Arduino libraries folder. We do this just to keep it as a backup.

Now restart the Arduino IDE if it was already running - or open it now. To test the module we have a demonstration sketch prepared, simply copy and upload the following sketch:/* Demonstration sketch for PCF8574T I2C LCD Backpack

After a few moments the LCD will be initialised and start to display our URL and the value for millis, then blink the backlight off and on. If the text isn"t clear, or you just see white blocks - try adjusting the contrast using the potentiometer on the back of the module.