Products Support Sales Company Scott Edwards Electronics, Inc.
Find by:   Product   Site Area   Part#     
 

LCD Serial Backpack® Interface for Alphanumeric LCDs

 BPK-000; size 2.8 by 1.4 in.

The LCD Serial Backpack® (BPK-000) is a universal serial interface for alphanumeric LCDs. Its minimal current draw (< 1mA), low cost, and LCD-based serial protocol make it the logical choice for microcontroller applications.

  • 2400/9600 baud serial input
  • Lowest current draw: < 1 mA
  • Simple protocol prints text, passes instructions to LCD
  • Display of choice for BASIC Stamp® applications
  • 10s of thousands sold!
Installation Data Basic Specs LCD Instructions Prices, More Info
 

Installation Data

Alphanumeric LCDs have a 14-pin interface header with the standard pin assignments listed in the table below. The header is physically arranged in either a single row of 14 solder pads, or 2 rows of 7 pads. The LCD Serial Backpack® has both types of pad layouts. Installation is just a matter of soldering the supplied header posts to the LCD, then soldering the Backpack to the posts. Everything lines up, so the installation is simple and secure.

Here are the LCD layouts that work best with the Backpack:

Standard LCD Pinout

This table is arranged to match the layout of a 2x7 header. With a 1x14 header, pins are numbered 1-14 in a row.

Pin Function Pin Function
13 Data bit 6 14 Data bit 7
11 Data bit 4 12 Data bit 5
9 Data bit 2 10 Data bit 3
7 Data bit 0 8 Data bit 1
5 Read/Write 6 Enable
3 V contrast 4 Data/Instruction (RS)
1 Vss (GND) 2 Vdd (+5Vdc)
back to top  

Basic Specifications

Size 2.8 x 1.4 in. (71 x 36mm)
Power requirements 4.8 to 5.5Vdc @ < 1mA
User connector 5-pin header; 0.025" posts on 0.10" centers
Connector pinout +5V GND SERIAL GND +5V
Serial Input RS-232 or inverted TTL, 2400/9600, N81
*Operating Temperature 0° to 50° C
Initialization switches LCD power; performs soft init
Instruction prefix ASCII 254 (0FE hex)
LCDs supported Alphanumeric, to 80 characters (e.g., 4x20)
*Note: The LCD Serial Backpack® is designed for use only with commercial-temperature-range LCDs. Extended-temperature LCDs require a negative bias voltage, which the Backpack does not support.
 

back to top  

LCD Instructions by Function

The LCD Serial Backpack® interface is an intelligent serial-to-parallel converter. It passes data to the LCD module, which prints it to the screen. To distinguish between text and instructions, the Backpack recognizes an instruction prefix, ASCII 254. The byte following ASCII 254 will be sent to the LCD as an instruction. For example, to clear the screen, send the instruction prefix (254) followed by the LCD clear-screen code (1).

This is different from our other serial LCDs, which use a protocol that's similar to a text terminal. The Backpack protocol's simplicity means that it can run at a very low clock rate (480kHz) for the lowest possible current draw.

Function ASCII Value
Clear screen 1
Home cursor 2
Blank display (retaining data) 8
Hide cursor 12
Show underline cursor 14
Move cursor 1 character left 16
Move cursor 1 character right 20
Scroll 1 character left 24
Scroll 1 character right 28
Set display address (position the cursor) 128 + location
Set character-generator address 64 + address
 

back to top  

 

Links for Additional Information

 
Scott Edwards Electronics Inc.
1939 S. Frontage Rd. #F, Sierra Vista, AZ 85635
phone 520-459-4802; fax 520-459-0623
e-mail info@seetron.com