Tarun Grover wrote:
> I've recently completed a project involving an LCD using this same
> controller.  What I found is that with the 2 LCD's I was using for testing,
> this initialization routine did not work.  What I found DID work was when I
> left out
> the first 3 'write4(3)' instructions.  Now, this goes against
> everything I've read on the internet and from Hitachi's Datasheet.  I
> only found 1 instance where someone used a different initialization
> scheme and this seemed to work for me.
>
> Was there anything wrong with what I was doing or do different LCD's behave
> differently (even though they use the same controller)?
>
>   
I had trouble with some VARITRONIX LCDs,
So here is what works till now for about 10 different LCD's

--    - Extra delay in Init procedure, after 4-bits setting,
--      needed for VARITRONIX MDLS-16268-series
  delay_1mS ( 40 )                      -- even long enough for Vcc as 
low as 2.7V
  HD44780_DataCmd_pin = low                 -- select command
  _HD44780_write_low_nibble ( 0b_0011 ) -- first init
  delay_1mS ( 5 )                       -- extra delay
  _HD44780_write_low_nibble ( 0b_0011 ) -- second init
  delay_10uS( 10 )                      -- extra delay
  _HD44780_write_low_nibble ( 0b_0011 ) -- third init

  _HD44780_write_low_nibble ( 0b_0010 ) -- set 4-bit interface
  delay_10uS( _HD44780_short_delay )    -- FOR SOME DISPLAYS 
(VARITRONIX) required delay
  _HD44780_Command( 0b_0010_1000 )      -- two lines, 5x7 (high nibble)
  _HD44780_Command( 0b_0000_1111 )      -- display on, cursor on, blink on
  _HD44780_Command( 0b_0000_0001 )      -- clear display
  _HD44780_Command( 0b_0000_0110 )      -- increment and no shift

Stef Mientki
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