LCD HD44780 Charset query

[Wilksey]

Hi,

I have been using the HD44780 on 16 x 2 and 16 x 4 LCDs for a while now, and I just went to look up a character code for a symbol and found that the datasheet shows 2 x "table 4" character sets, noted by ROM Code A00 and ROM Code A02.

But I can't see it mention this alternative code anywhere else, I wondered if it had to do with the 5x8 vs 5x10 char size so I changed the intialisation to select the alt char size but it made no difference.

Does anyone know if this is an alternative built into some variant or if the 2nd charset is built into the HD natively, if so how does one go about selecting it as I can't seem to find anything useful in the instruction set.

It is not that I necessarily need it but it does contain some chars that I have constructed myself but we are limited to 8 chars for the custom CGROM so it would be quite handy to have access to them.

For information the datasheet can be found here: https://www.sparkfun.com/datasheets/LCD/HD44780.pdf

Cheers

Wilksey

[amyk]

Look at the second page of the datasheet. 'A00 is the "Japanese standard font", 'A02 is the "European standard font". They are separately orderable parts... or rather, were, since Hitachi itself hasn't produced these in over a decade. As such, it is highly unlikely you are actually using a genuine Hitachi HD44780 in your display. Note that the datasheet you linked is from 1999.

[Wilksey]

Hi amyk,

Ah, that was an oversight on my part, seems as though I have a "Japanese standard font" variant, I know it is an old datasheet / controller, most are "Compatible" but the controller in my LCD is true to the datasheet.

I guess as it is controller device part dependant I wouldn't be able to tell regardless as most are "blob" chips on these LCDs and all of the ones I have used seem to have the A00 charset.

Ah well, it would have been nice but no worries.

Thanks for the info!

Cheers