I haven't read the code but if it was meant for the '84 and uses 8 bit
data bus, PORTA was probably used for control lines.

Remember on '74 that PORTA has analogue to digital converters which
defualt to analogue mode on power up.  You have to set them digital mode.
That's what I would check.

On Fri, 14 May 1999, Jay Mielke wrote:

> Hi all,
> I am trying to get an Optrex 4X16 LCD to work (HD44780) using the code from
> Peter Ouwehand's home page.  The catch is I am using a 16C74A as opposed to
> the 16C84.  Has anyone else tried this?  I turn the circuit on and the first
> and third lines of the LCD are filled in with block characters, the second
> and fourth lines are blank.  I am using the full 8-bit interfacing.
> FRUSTRATION!!!!!!  Help me!! Help me!!!! I cannnnnn't seeeee!!!!!
>
> Thanx in advance
> Jay Mielke
>