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 Feb 28 2015, 02:51 PM
Anupam Biswas
I am doinga project on gsm based home automation.I have done alittle study about at commands.I am using Atmel 89c51 with yhe gsm module.I am unable to receive any message via the module.The simulation is done on proteus and i am using a virtual terminal.Can anyone please help me?Thanks in advance.
Tue Feb 24 2015, 12:47 AM
MrCurious
is Stat a global variable too? you reference it in Chan's "disk_status" function.
Sat Feb 21 2015, 09:10 PM
Harikumar
കൊള്ളാം
ExperimenterUK
Fri Feb 20 2015, 06:28 AM
@sugikz.. I have asked Ajay about it, he'll soon sort it out
Thu Feb 19 2015, 12:22 PM
sugikz
"Sorry no bots allowed! You entered two different email addresses. Please enter a valid email address in the two fields provided"
Thu Feb 19 2015, 12:21 PM
sugikz
this are the problem notice box;
Thu Feb 19 2015, 12:20 PM
sugikz
yes, i still got stuck on email problem, i've used gmail, yahoo, and told some friends of mine to sign up on the site, but they face the same problem as iam,
Thu Feb 19 2015, 05:48 AM
sjeeva
hi, is any doing a project on raspberry pi
Thu Feb 19 2015, 05:48 AM
sjeeva
hi
Wed Feb 18 2015, 06:21 PM
IJAZ
sir i do my final year project.and want to interface ambient light sensor(tsl45313) with microcontrollar,sir plz help me in programing and interfaceing..waiting for your's positive responce

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arunkollam
Wed Feb 25 2015, 05:28 AM
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Posted By sankalp_s
Thu Feb 26 2015, 09:27 PM
What are you trying to make ?ExperimenterUKsir i w...
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Posted By ExperimenterUK
Thu Feb 26 2015, 12:58 AM
We seem to be moving away from the original projec...
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Posted By ajay_bhargav
Wed Feb 25 2015, 02:02 PM
You will need a 64 bytes buffer that will be writt...
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Posted By PsySc0rpi0n
Wed Feb 25 2015, 09:24 AM
I've already read that tutorial and almost all oth...
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Wed Feb 25 2015, 04:56 AM
brightness control is going to be tough job as you...
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Wed Feb 25 2015, 04:36 AM
I've already read that tutorial and almost all oth...
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Posted By sankalp_s
Tue Feb 24 2015, 07:18 PM
The attached code is for up to 16 LEDs.Just point ...
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Mon Feb 23 2015, 11:49 PM
Sir in this code, led blow constantly and nothing...