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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Sat May 28 2016, 04:34 PM
kibrom berhe
c code for locker security system based on rfid and gsm
ExperimenterUK
Wed May 25 2016, 05:05 AM
@ Ramanjaneyulu, post in forum,explain your problem
Mon May 23 2016, 11:34 PM
Ramanjaneyulu
Hi, I Am using at89c4051 for my application, I want 5u sec dely.. Up to 1milli sec iam able to producing delay. Beyond the 1milli second, I am unable to produce the acceurate dely. Plz any one help me
Sat May 21 2016, 09:51 PM
A K
i want to mak an auto dialer using gsm and atmega 16. please helpe me how to write a code to auto dial a number saved in sim
Sat May 21 2016, 10:42 AM
Alec
Hi im trying to program my 89s51 with a usbasp so any ideas on the circuit?
Wed May 18 2016, 10:08 AM
Tashu joshi
anyone know how to develop
Wed May 18 2016, 10:07 AM
Tashu joshi
i'm working for resporatry system using 8051,
Wed May 18 2016, 10:06 AM
Tashu joshi
i'm developing a respiratory system using Arduino
Fri May 13 2016, 11:03 AM
MEGHANA
i need c code for counting frequency of two sensors and compare these frequencies and it has to give high/ low signal after comparision
ExperimenterUK
Tue May 10 2016, 05:02 PM
@Suren ..create a thread in the 8051 Discussion Forum to discuss your problem

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zaft93
Sun May 15 2016, 01:52 AM
CELEBI
Thu May 12 2016, 08:28 AM
Suro1996
Wed May 11 2016, 06:07 PM
yigithan
Sat May 07 2016, 09:09 PM
jaque
Fri May 06 2016, 07:51 PM
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Wed May 04 2016, 11:16 AM
pd
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Posted By ExperimenterUK
Sun May 15 2016, 10:58 PM
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Posted By zaft93
Sun May 15 2016, 01:55 AM
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Posted By ExperimenterUK
Fri May 13 2016, 07:59 PM
If you want only one relay to be on at a time the ...
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Posted By CELEBI
Fri May 13 2016, 06:16 AM
Yes. It must be as you said. It must be 1.5 second...
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Posted By ExperimenterUK
Thu May 12 2016, 08:35 PM
Here is one way.If you have the Keil compiler you ...
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Posted By ExperimenterUK
Thu May 12 2016, 05:20 PM
Sorry I don't understand what you want.Is that 1.5...
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Posted By CELEBI
Thu May 12 2016, 08:53 AM
Hello Guys, I want to make a Project with 89s51 bu...
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Wed May 11 2016, 09:28 PM
No this is all I've got, the algorithm I think is ...
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Posted By Suro1996
Wed May 11 2016, 09:27 PM
Is this all the code you have ?As it is, it will n...
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Posted By Suro1996
Wed May 11 2016, 07:31 PM
Hello, I am new to assembly programming and I am h...