LCD buzy bit in 8051 initialization

[vedaprabhu]

In mazidi and mazidi pg 252(2006 edition) for the case of checking the buzy bit during initialization of LCD they are sending a low to high pulse to enable pin instead of a high to low as done in previous programs.Can anybody please explain why this special syntax for checking buzy bit?or is it a printing mistake?

 

[mak_goel]

Is it really required to check the busy flag. You can init the LCD by using Delay Programe.

Mak

 

[cdcll]

it is needed to check the busy flag, to ensure the LCD works properly

 

[mak_goel]

I couldn't understand perfectly till now by checking the busy flag, As per my view LCD is bing used to be written on that and two process are there to solve the purpose:
1) Delay Process
2) By checking busy flag.

I am using the Delay process and facing no problem. You are saying it is required to check the busy flag continuously to check wheather LCD is working properly or not, i couldn't understand this thing.

Thanks
Mak

 

[vedaprabhu]

Hey guys thanks for the quick responses.
There are two ways to initialize an LCD :

1)Introduce delay after every command call or data call
2) Use buzy bit flag D7 and check whether LCD is buzy or not and then ensuring it is free do any writing.

My problem refers to the use of "enable" in context of a buzy bit .Isn't enable a high to low pulse to be sent in order to latch the data at pins into LCD ?Mazidi does this the other way round, that is low to high pulse is sent in case of using buzy bit for initialization.

Hope I put my point across :|

 

[sci-3d]

I think, sometime it is not necessary to check status, I grounded this pin by using software delaying is ok, see:

https://mcu-programming.blogspot.com/2006/09/lcd-interfacing.html

however. it is C not Assembly.

 

[VSMVDD]

when one builds a hierachie of sample designs and code

to implement conformaty to top level designs

api and cpi offer all pins up to the lowest level projects

this is common practice

although its not strictly needed

 

[yousafzai]

I think software delay helps in saving microcontroller resources but it takes extra time.......

 

[vedaprabhu]

ok guys lets get it clear.I agree one can use software delay.
Set that aside for the time being.
My question was - to latch data into lcd, should one send high to low to enable pin or low to high?

PS: It is generally high to low right? In case of buzy bit why low to high?

 

[csaba411]

Sending a low to high pulse to enable pin is the only way to read or write to the 44780 !

 

[txdx2005]

you can use delay to replace the check busy