LCD Read/Write operation

jab99407 · Dec 16, 2019

I am looking help to understand datasheet of 16*2 LCD. Please look at this datasheet **broken link removed**

Page 3 Timing char, I do not understand read and write operation there are three control signals RS, R/W and E

if I want to send one byte to LCD display How these three signals work for read and write operations ?

MaxHeadRoom78 · Dec 16, 2019

Look up the papers (PDF) by Julyan Ilett, part 1 and part 2, explains it all.
Max.

DrG · Dec 16, 2019

jab99407 said:
I am looking help to understand datasheet of 16*2 LCD. Please look at this datasheet **broken link removed**

Page 3 Timing char, I do not understand read and write operation there are three control signals RS, R/W and E

if I want to send one byte to LCD display How these three signals work for read and write operations ?

The three signals work just as in the diagram, but remember that RS (Register Select) will determine whether what is read or written is a register or data.

jab99407 said:
if I want to send one byte to LCD display How these three signals work for read and write operations ?

Look at the table on Page 6. See the state of RS and R/W for different actions?

Ian Rogers · Dec 16, 2019

Are you using a picaxe controller?? How many pins? are you connecting 2 control and 4 data?

The normal way with the picaxe is serially using an LCD backpack

jab99407 · Dec 16, 2019

Ian Rogers said:
Are you using a picaxe controller?? How many pins? are you connecting 2 control and 4 data?

The normal way with the picaxe is serially using an LCD backpack

No, I had to find out how we send data to the LCD So i looked at the datasheet But I do not understand what should I do if I want to send one byte data to LCD

Table can help me to understand read and write operation 16*2 LCD

Control signals	Write operation	Read Operation
RS	?	?
RW	?	?
E	?	?

DrG · Dec 16, 2019

jab99407 said:
No, I had to find out how we send data to the LCD So i looked at the datasheet But I do not understand what should I do if I want to send one byte data to LCD

I think you need a little better understanding of what sending a byte of data to the controller means. The Table on page 6, which I referenced, explains it - but you may not know enough background to understand that.

Two papers were suggested in a previous post: They are linked below. Reading through those may help.

https://www.wizard.org/auction_support/lcd1.pdf

https://www.wizard.org/auction_support/lcd2.pdf

jab99407 · Dec 16, 2019

so I this is sequence to write command or data to lcd
/*LCD 8 bit example
rs => Register Select [Command : Data]
0 => Command
1 => Data Set RS high for Data.
rw => Read/Write [Write : Read]
0 => Write
1 => Read
en => Enable signal [High to Low]

Pommie · Dec 16, 2019

That is the right sequence but the display has to be properly initialized as explained in the datasheet or it won't do anything.

Mike.

LCD Read/Write operation

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