Commands and Instruction set

Only the instruction register (IR) and the data register (DR) of the LCD can be controlled by the MCU. Before starting the internal operation of the LCD, control information is temporarily stored into these registers to allow interfacing with various MCUs, which operate at different speeds, or various peripheral control devices. The internal operation of the LCD is determined by signals sent from the MCU. These signals, which include register selection signal (RS), read/write signal (R/W), and the data bus (DB0 to DB7), make up the LCD instructions (Table 3). There are four categories of instructions that:


  • Designate LCD functions, such as display format, data length, etc.
  • Set internal RAM addresses
  • Perform data transfer with internal RAM
  • Perform miscellaneous functions



Table 3: Command and Instruction set for LCD type HD44780


Although looking at the table you can make your own commands and test them. Below is a breif list of useful commands which are used frequently while working on the LCD.


No. Instruction Hex Decimal
1Function Set: 8-bit, 1 Line, 5x7 Dots0x3048
2Function Set: 8-bit, 2 Line, 5x7 Dots0x3856
3Function Set: 4-bit, 1 Line, 5x7 Dots0x2032
4Function Set: 4-bit, 2 Line, 5x7 Dots0x2840
5Entry Mode0x066
6Display off Cursor off
(clearing display without clearing DDRAM content)
0x088
7Display on Cursor on0x0E14
8Display on Cursor off0x0C12
9Display on Cursor blinking0x0F15
10Shift entire display left0x1824
11Shift entire display right0x1C30
12Move cursor left by one character0x1016
13Move cursor right by one character0x1420
14Clear Display (also clear DDRAM content)0x011
15Set DDRAM address or coursor position on display0x80 + address*128 + address*
16Set CGRAM address or set pointer to CGRAM location0x40 + address**64 + address**
Table 4: Frequently used commands and instructions for LCD
* DDRAM address given in LCD basics section see Figure 2,3,4
** CGRAM address from 0x00 to 0x3F, 0x00 to 0x07 for char1 and so on..

The table above will help you while writing programs for LCD. But after you are done testing with the table 4, i recommend you to use table 3 to get more grip on working with LCD and trying your own commands. In the next section of the tutorial we will see the initialization with some of the coding examples in C as well as assembly.

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Conversation

Tue Nov 29 2016, 02:49 PM
jaykumar
Dear sir, elevator microprocessor control , the vendor locked the control, pls help me how can we decode the password
Sat Nov 26 2016, 10:24 AM
manikanta B
hello i know about gsm,gps and zigbee but i dont know how to use them while programming. can anyone suggest me how to use them
ExperimenterUK
Sat Nov 19 2016, 07:09 PM
@Protaz.. Really you would be better off asking on one of the many Arduino user sites
Fri Nov 18 2016, 05:39 AM
Protaz
Hi, am new in programing, but I have few skills in electronic. I want to make an automatic timing system for institutions using arduino uno. Any one to assist me how to program the microcontoller?
Tue Nov 15 2016, 04:45 AM
Hemangi patel
hello, i am working on atmega128 board and i want to interface with sd card with using fat32 file system. i am totaly new in this field .so pls anyone can u suggest me some imp links.thanks
Thu Nov 10 2016, 01:40 PM
ajith raj
hi frds i make voice control robot using blutooth module
Wed Oct 26 2016, 08:23 AM
ishalt
is it possible to completly get the robot running from java code
Sun Oct 23 2016, 05:50 PM
mamata thakur
plz send full mini project report for ic 741&ic 555 tester
Wed Oct 19 2016, 03:30 PM
riddhi1296
can you provide an explanation for the inverter 8051 code and how it works
ExperimenterUK
Sat Oct 15 2016, 12:15 AM
@snaya. Create a thread in the 8051 forum for your questions

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Jonathan.kei
Mon Nov 21 2016, 04:30 PM
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Mon Nov 14 2016, 05:54 PM
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Wed Nov 02 2016, 02:03 PM
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Thu Oct 27 2016, 01:54 PM
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