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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ajay_bhargav
Mon Mar 23 2015, 04:22 AM
You can only simulate simple 8051. RD2 support is not there in proteus. However there are similar atmel varient which can be used instead.
Sun Mar 22 2015, 07:24 PM
Aryan Nath
How can i Simulate microcontroller project in Proteus that uses P89V51RD2
Thu Mar 19 2015, 02:45 PM
Peter Mann
I have tried to register on the site, but it keeps saying I've entered two different email adresses - but I haven't!
ajay_bhargav
Sun Mar 15 2015, 08:25 PM
I did not get new message indication.. strange..
ExperimenterUK
Sun Mar 15 2015, 08:18 PM
slight delay, my connection failed
ajay_bhargav
Sun Mar 15 2015, 08:08 PM
Atleast you chat on our website if not anywhere else
ajay_bhargav
Sun Mar 15 2015, 08:08 PM
Hi Phil..
ExperimenterUK
Sun Mar 15 2015, 08:05 PM
Hi Ajay
gsdvprasad
Fri Mar 13 2015, 04:20 PM
Can you help me how to change the text on led display in proteus simulation?
ajay_bhargav
Sat Mar 07 2015, 07:48 AM
@Shoukat, its general purpose PCB board for soldering components

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marti
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Posted By iamalien
Sat Mar 28 2015, 04:48 AM
To answer it as vaguely as the question, you just ...
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Posted By iamalien
Sat Mar 28 2015, 04:27 AM
i thought that lighting led for more times should ...
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Posted By mayank058
Fri Mar 27 2015, 06:46 AM
Dear Sir, I am working on MCB2300. I...
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Thu Mar 26 2015, 09:06 PM
Have a look through the list of projects in our do...
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Posted By ExperimenterUK
Thu Mar 26 2015, 09:03 PM
As you say, each column is only on for part of the...
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Thu Mar 26 2015, 07:43 AM
Hello guys, i am doing a project on display using ...
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Hey I have to make a project on Digital calendar u...
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Wed Mar 25 2015, 05:34 AM
Thank you sir I make a try with the transducer and...
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Posted By ExperimenterUK
Tue Mar 24 2015, 05:32 PM
There would be no any biasing circuit?only a shunt...
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Posted By ExperimenterUK
Tue Mar 24 2015, 04:55 PM
Your suggestion worked Mr. ExperimenterUK. I tried...