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

Wed Jul 01 2015, 05:14 PM
ShubhamBansal1996
i am making a project of connecting 4 8051's using a can bus for which i am using mcp2515 and mcp2551.but before making it i want to ensure it works by simulating it on proteus though the two ic's mentioned above dont seem to have models in proteus so is there anyone who can help me with that
ExperimenterUK
Tue Jun 30 2015, 05:24 PM
@sachinmm The 8051 timer can't do 1 second. It can do 50ms so count 20 times
sachinmm
Sat Jun 27 2015, 05:01 AM
how calculate 1 second delay in 8051 by using timer and what value should be store in TH0 & TLO register??
sachinmm
Fri Jun 26 2015, 08:25 AM
hello sir plz tell me how to know the 74HC165 parallel in serial out ic is fauty or not?
Wed Jun 24 2015, 08:24 AM
ben mutuku
How can one use XOR gate to ensure the first output is '1' and the next is '0'?
ExperimenterUK
Wed Jun 17 2015, 01:37 AM
@baz..try adding a hash and a semi colon
Sun Jun 14 2015, 06:31 AM
baz
@ExperimenterUK no..i dont do that i just type message example.. Hello my name is baz and then i click send message,
ExperimenterUK
Sun Jun 14 2015, 01:55 AM
@baz..did you end your message with a hash and a semi colon
Sat Jun 13 2015, 06:48 PM
asif Jamadar
I want the program for v/f control technique of 3 phase induction motor
Sat Jun 13 2015, 07:06 AM
baz
@ExperimenterUK okay thank you...but now I already complete and my dot matrix already light up but when i send message from pc to my hardware project it doesnt show any message on my dot matrix..its only blinking when i click send message....I really dont know whats the problem...I had follow all the steps...schematic and use the coding that have been provided..is it because firstly i had wrong burn the coding in AT24C16?? Is that effect ????

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Posted By Nals99
Fri Jul 03 2015, 09:34 AM
Here you have an example using timer 0: void delay...
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Fri Jul 03 2015, 08:52 AM
Hi guys...I'm having some problems to transmit dat...
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@ajay_bhargav i will not prefer costly ic because ...
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@ExperimenterUKThanks a lot for correcting my misc...
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@ExperimenterUK Thank you for your simple and usef...
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Tue Jun 30 2015, 05:45 PM
The 8051 timer can't do 1 second. It can do 50ms, ...
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Tue Jun 30 2015, 05:38 PM
Debugging is the process of finding out why your ...
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Tue Jun 30 2015, 05:21 PM
You may have misunderstood some of the terms used....
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Mon Jun 29 2015, 06:03 PM
Suppose the ILI9320 TFT LSB & MSB pins are con...
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Hello everyone,I wanted to know the basics of debu...