LCD 1602A initialization 4 bits mode

Thread Starter

simozz

Joined Jul 23, 2017
125
Hello,

I need to initialize an LCD display in 4 bits mode and I have a few doubts.

Referring to the attached datasheet, at page 17 it is shown the flow chart.

Screenshot_2022-02-25_12-19-31.png

Does the red rounded data refers to the high nibble and the green one to the lower nibble ?

Then, what does mean I/D ?
Screenshot_2022-02-25_12-22-23.png

Thanks,
s.
 

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Ian Rogers

Joined Dec 12, 2012
1,136
Does the red rounded data refers to the high nibble and the green one to the lower nibble ?
No! When you initialise these things only the top nibble is required until the function set command is issued.

Send 0x30 ( ie DB4 and DB5 ) three times with a delay. Then either 0x30 or 0x20 for 8 / 4 bit interface along with the lower nibble containing the size.. ie one two lines..
 

ErnieM

Joined Apr 24, 2011
8,375
Kudos for working this out for yourself rather than copying one of a myriad of code examples on the innerwebs.

If you check the column names "DB7 DB6 DB5 DB4" refer to the input lines of the LCD, not whatever you happen to be driving it with. DB3, DB2, DB1, and DB0 are not actively driven but can be connected to either ground or VDD.

I/D sets the cursor and character memory dir, set to high so cursor moves to right and memory increments on a load.
 

Thread Starter

simozz

Joined Jul 23, 2017
125
Thanks !

Yesterday I was a little bit confused about how interpret that datasheet.. I have to say that it is quiet poor in its explanations.

That one attached here is far more complete. From page 17 the commands are explained very clearly, so I finally made the LCD and firmware work.

Perhaps it will be useful to someone that will need to use a 1602A in the future.
 

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