8/9/2019 7234791 LCD Display Drivers Lecture

1/16

Writing to an LCD

HD44780 LCD Drivers

8/9/2019 7234791 LCD Display Drivers Lecture

2/16

16x1 LCD Module

16 characters, 1 row

8-bit or 4-bit parallelinterface

Industry standard

HD44780 controller Variations: backlight,

polarizer, reflective,

wide viewing angle.

http://www.crystalfontz.com/products/1601a/index.html#CFAH1601ANYGJP

8/9/2019 7234791 LCD Display Drivers Lecture

3/16

HD44780U (LCD-II)

Dot Matrix Liquid Crystal Display Controller/Driver

Can be controlled by 4- or 8-bit mode

Can control up to one or two 8-character lines

Low power supply (2.7V to 5.5V) 5x8 and 5x10 dot matrix possible

80 x 8-bit Display Data RAM (80 characters max)

9,920-bit character generator ROM for 240 fonts

8/9/2019 7234791 LCD Display Drivers Lecture

4/16

Interfacing to the LCD

8/9/2019 7234791 LCD Display Drivers Lecture

5/16

MappingCharacter Codes

to CharacterPatterns

8/9/2019 7234791 LCD Display Drivers Lecture

6/16

Display Data RAM (DDRAM)

To write data to display, store individual

characters into DDRAM

LCD controller reads DDRAM and displays thedata represented in 8-bit character codes

Can store up to 80 characters

16x1 can be implemented as a 2-line display of8 characters (8x2) using same controller

8/9/2019 7234791 LCD Display Drivers Lecture

7/16

Interfacing to the MCU

8/9/2019 7234791 LCD Display Drivers Lecture

8/16

Pin Functions

8/9/2019 7234791 LCD Display Drivers Lecture

9/16

Interfacing to the MCU

8/9/2019 7234791 LCD Display Drivers Lecture

10/16

8/9/2019 7234791 LCD Display Drivers Lecture

11/16

Instruction Descriptions

display clear 20H to all locations cursor home sets address counter to DDRAM 0 display on/off control

cursor on/off display character blink

cursor or display shift function set

DL: data length interface (4 or 8 bits) N: number display lines F: character font

entry mode what happens after character write I/D: DDRAM incremented or decremented S: shift display left or right

8/9/2019 7234791 LCD Display Drivers Lecture

12/16

[1] Hitachi. HD44780U (LCD-II) Dot Matrix Liquid Crystal Display Controller/DriverDatasheet. www.datasheet4u.com/html/H/D/4/HD44780UA00FS_Hitachi. df.html

8/9/2019 7234791 LCD Display Drivers Lecture

13/16

Set Function: 8 bite mode

Set Function: 4-bit mode

Function Set: #lines and font

Clear display

Set entry mode

Display Off

8/9/2019 7234791 LCD Display Drivers Lecture

14/16

Character Generator ROM

Create your ownfonts: 5x8 or 5x10

dot patterns

CGRAM can also be

used as generalpurpose RAM

8/9/2019 7234791 LCD Display Drivers Lecture

15/16

LCD Segment Displays

Lower tech, earlier design, cheap

Here, each segment is made of 7 bars

8/9/2019 7234791 LCD Display Drivers Lecture

16/16

Coding Segments

Each bar in a segment is labeled with a letter

Create map of bars to display each letter and number