Author Topic: HD44780 8-bit Initialization Rationale  (Read 2499 times)

Tim_Cole

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HD44780 8-bit Initialization Rationale
« on: September 15, 2014, 12:56:50 AM »
Greetings all,
I'm using an old vanilla HD44780-style LCD screen, and for the first time, I'm using 8-bit mode. Every piece of example code I've shows setting 8-bit interface mode by writing 0x30 three times, with varying delays between writes. The hex value makes perfect sense, I won't argue with a method that's known to work, but why do you write it three times?

Cheers, Tim

Michael_L

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Re: HD44780 8-bit Initialization Rationale
« Reply #1 on: September 16, 2014, 09:33:03 AM »
Sometimes the repeated function set command is needed to essentially "wake up" the controller.  It may or may not be necessary in all applications, but I suppose at the very least it makes for a more robust initialization.

Tim_Cole

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Re: HD44780 8-bit Initialization Rationale
« Reply #2 on: September 16, 2014, 01:55:51 PM »
That makes sense - whack the sucker with a stick to make sure you've got its attention.  It certainly won't hurt, but I'd wondered if there was some other subtlety. Thanks!

 

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