Specifications

mikroElektronika | Free Online Book | PIC Microcontrollers | Appendix B: Examples

Control of operating

4 RS

D0 – D7 are interpreted as commands

D0 – D7 are interpreted as data

5 R/W

Write data (from controller to LCD)

Read data (from LCD to controller)

6 E

From 1 to 0

Access to LCD disabled

Normal operating

Data/commands are transferred to LCD

Data / commands

7 D0 0/1 Bit 0 LSB

8 D1 0/1 Bit 1

9 D2 0/1 Bit 2

10 D3 0/1 Bit 3

11 D4 0/1 Bit 4

12 D5 0/1 Bit 5

13 D6 0/1 Bit 6

14 D7 0/1 Bit 7 MSB

LCD screen

The LCD screen consists of two lines with 16 characters each. Every character consists of 5x8 or 5x11 dot matrix. This

book covers the 5x8 character display, which is indeed the most commonly used.

Display contrast depends on the power supply voltage and whether messages are displayed in one or two lines. For this

reason, varying voltage 0-Vdd is applied on the pin marked as Vee. Trimmer potentiometer is usually used for that

purpose. Some LCD displays have built in backlight (blue or green diodes). When used during operation, a current limiting

resistor should be serially connected to one of the pins for backlight (similar to LED diodes).

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