Please Help me On LCD Concept

[Naga Suresh]

hi,

  im using 16×2 lines hd44780 lcd ,

 

according to data sheet rs=0,r/w=1 high means read mode,this mode is used while reading busy flag,

 

rs=1,r/w=1 means reading contents of the CGRAM,DDRAM…

 

lcd is output device, what is the use of reading DDRAM/CGRAM contents? is there any real time application regarding this mode of operation??

if yes please let me clarify what are they???

[Ashutosh Bhatt]

hello Suresh,

you are correct. LCD is output device. reading the content of CGRAM / DDRAM is hardly used. how ever the option is given for any posibility. 

[AJISH ALFRED]

Hi Naga,

The reading option is normally used to check the ‘busy flag’. The LCD module is a very slow device. Once the data is written to it, the internal controller of it will take time to finish the display process of the same data. The user is allowed to write data again once the controller reset the ‘busy flag’ after processing the previous data.

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