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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ExperimenterUK
Thu Nov 20 2014, 06:00 PM
@Mehboob.. I don't think you can do that.
Sat Nov 15 2014, 06:41 AM
Mehboob
Pls can you send me code in c of PWM generation using UART/serial port in 8051.
Fri Nov 14 2014, 02:51 PM
mohammad aqil
NEED A BOOK ON MICROPROCESSOR AND INTERFACING BY D.V.HALL. RIGHT NOW, I SHALL BE VERY THANK FULL TO U....
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m
please code hex project avr blood pressure monitor
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Lambo
hi mate, whats the ajay-bhargav? tell us more pls
ExperimenterUK
Wed Nov 12 2014, 12:56 AM
@tmtm000.. have you been able to join ?
ExperimenterUK
Wed Nov 12 2014, 12:54 AM
@Alice..become a member,then send a PM to ajay_bhargav the site owner.
Tue Nov 11 2014, 03:58 AM
Abhishek Bansal
Thanks a lot for your informative tutorials!
Mon Nov 10 2014, 09:03 AM
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Posted By ExperimenterUK
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@ExperimenterUKI make small table to observe Outpu...
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@ExperimeterUKForgot my last question.As i told be...
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@ExperimenterUKI make small table to observe Outpu...
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@ExperimenterUKThank u. I do it. Ohne Period it's ...
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You set the on/off times here as 47%float PWMcom...
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Right now i am studying Bootloader.I want to writ...
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I am using PSoC 5LP.pls check the attached design ...
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Thanks for the prompt response, I will try it out ...
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this one sir! i attached the whole project! ...