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)
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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Tue Oct 06 2015, 08:22 AM
HI you looking for ideas or you have solution
Fri Oct 02 2015, 03:39 PM
poojitha: projects on wireless communication between two microcontrollers
Thu Oct 01 2015, 04:38 PM
hey! i wanted to simulate my circit using proteus. i have a sugar cube relay in my circuit....but i dont know which one is that in the device libraries of the software. any help? thankyou.
Tue Sep 29 2015, 09:40 PM
@Michal, that rocket is too heavy for itself and trust is not enough unless afterburners are fed with fuel properly.
Sat Sep 26 2015, 08:19 PM
Hello, its possible to make a amateur rocket with this engine, or something simillar, which be able to flight?
Thu Sep 24 2015, 10:38 AM
Ir Switch sir.
Wed Sep 23 2015, 01:10 AM
@engr1931 which project ?
Tue Sep 22 2015, 11:57 AM
Hello sir, is it ok to use 12.000MHz oscillator in IRswitch, because the requirement written in the post is 11.059MHz. And i use PIC1018 as an Ir receiver
Mon Sep 21 2015, 04:15 PM
Hello sir, your blog is kind of helpful for us especially students. May I know do you have the coding for decimal to binary using proteus 8. My mini project is about to convert decimal to binary just like a calculator. The output is LCD. A bit confusing is the decimal to binary coding on proteus 8. pls help thanks.
Sun Sep 20 2015, 09:08 PM
Have you searched our Embedded GSM Development and GSM and CDMA Discussion forums ?



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Posted By praveenraoms
Tue Oct 06 2015, 01:06 PM
hi i want to know the code to access the geographi...
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Wed Sep 30 2015, 08:54 AM
how to used polling method in this?? my code is co...
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Posted By ajay_bhargav
Tue Sep 29 2015, 09:39 PM
__irq is just compiler directive to wrap IRQ routi...
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Tue Sep 29 2015, 09:36 PM
The comment does say the time values as per the th...
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Tue Sep 29 2015, 09:33 PM
are you testing this on Proteus? or MplabX simulat...
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Tue Sep 29 2015, 09:31 PM
[Topic moved to ARM Development Forum]
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start with reading datasheet. SPI interface on LPC...
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Tue Sep 29 2015, 09:27 PM
I am not sure you've solved it or not but "USARTRe...
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Tue Sep 29 2015, 06:31 PM
i am confused in "__irq" it is uesd??sachin...
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Tue Sep 29 2015, 11:11 AM
my I2C.c file=>>/*********************************...