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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Conversation

hiast
Thu Jun 16 2016, 03:03 PM
help please how do i initiate port 3 as an input port in assembly? acutely there is push switch connecting to p3.2 push switch connecting to p3. 3 push switch connecting to p3.4 push switch connecting to p3.5 and i need to call function when the user pressed the push switch for the previous pins (not used as counter and not as timer… just call a function ( do special thing) when any push switch is pressed ???????
Mon Jun 06 2016, 12:02 PM
nida hussain
hi.. i need some help with keypad interfacing code.like i want to write a code in c language that takes an input of 2 digit numbers from a keypad interfaced with 8051 mc and stores the entered values in some array
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

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dyoussef
Wed Jun 29 2016, 07:29 PM
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hiast
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alex1311
Thu Jun 09 2016, 06:57 AM
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ExperimenterUK Avatar
Posted By ExperimenterUK
Thu Jun 30 2016, 05:44 AM
I think the display/ editor software added the a...
dyoussef Avatar
Posted By dyoussef
Wed Jun 29 2016, 07:34 PM
Hello, I am referencing this project: http://www.8051projects.net/wiki/I2C_Implementation_on_PICI am using PIC16F1847 and XC8 so I've had to make a few changes to the code. While making changes, my compiler gave me an error for the I2CWait function for the while statement. It says "unexpected token amp". Here is the line in question:while ((SSPCON2 & 0x1F ) || ( SSPSTAT & 0x04 ) );I changed the register names to be consistent with my PIC but it didn't solve the problem.What changes do I need to make to this function so that this error does not occur?
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Posted By ExperimenterUK
Wed Jun 22 2016, 07:54 PM
I can't see why it should work sometimes and not o...
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Posted By ExperimenterUK
Wed Jun 22 2016, 12:58 AM
You could use T0 and T1 to trigger interrupts but ...
Karan123 Avatar
Posted By Karan123
Tue Jun 21 2016, 04:40 AM
I am not Getting you . the project is to interfac...
Karan123 Avatar
Posted By Karan123
Tue Jun 21 2016, 04:34 AM
Hello,Thanks , It Works . Master-Slave address Ma...
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Posted By alex1311
Mon Jun 20 2016, 11:38 AM
Football is my passion and I have dreamt of becomi...
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Posted By ExperimenterUK
Fri Jun 17 2016, 11:00 PM
>But Can't modify code at Receiver End for Differe...
hiast Avatar
Posted By hiast
Fri Jun 17 2016, 03:25 PM
thanks for help,i wanted to write this code as you...
Karan123 Avatar
Posted By Karan123
Fri Jun 17 2016, 12:19 PM
I don't your applications . But below should help ...