H44780 LCD driver Enable Line

Dec 10, 2003 6 Replies

I am working on a LCD display. The display driver has got a line E (Enable) In some documents i have seen that you have to toggle this line 1 to 0 so that what ever data is there at input of driver gets interpreted. In some other documents there is no mention of state of E line . Some body please clarify.


NITIN


You can look for some infromation here

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under timing. You have on this page a good initialization routine, it is very important to do it in the right order with right delays.

It is necessery to use E line.

Yes, it does need to be toggled. Also, if you look at the timing requirements for this line, you will see that it requires a very fast rise and fall time on the clocking edge, which sometimes means that a buffering chip is required.

The name of the E line is inherited from the Motorola 6800 bus. It is indeed the bus cycle clock which times the read and write cycles, so instead of separate read and write strobe pulses there are an enable pulse and a direction select (R/W).

HTH

Tauno Voipio tauno voipio @ iki fi

Thank you all for the help. I am planning to provide an external pull on E line . before wrtting or reading from the driver the correspondg thg will be put on ports of MCU and then E line will be toggled from E = 0 and then to 1 Is this the way it should be done

Nitin

If you have 8051 controller and you connect pin E to other than port P0 pins, you don't need external pull-up.

Yep.

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