User defined characters-alfanumeric LCD

[ady689]

Haw I write a rutine in MPASM to generate user defined charcters on a alfanumeric LCD, i find a similary example but is write in C++ and i dont undersant..nothing....Can you help me?

 

[bananasiong]

Hi,
Perhaps you need these:

http://winpicprog.co.uk/pic_tutorial3.htm

 

[ady689]

I read this tutorial, and he is not what i want




Purpose: - Load a user-defined character definition into the HD44780 character generator memory.

Quick explanation on how to implement user-defined characters:

First you will need to make a pixel definition for the characters
you want to use. Below is the pixel definition for an underlined
'0' (char code 0x30) based on a 5x7 dots character definition:

| bits | byte
row | 76543210 | value
------------------------
000 | xxx | 0x0E
001 | x x | 0x11
010 | x xx | 0x13
011 | x x x | 0x15
100 | xx x | 0x19
101 | x x | 0x11
110 | xxx | 0x0E
111 | xxxxx | 0x1F

 

[bananasiong]

Misunderstood.
I've never tried this, but is the datasheet of HD44780 helpful enough?

 

[ady689]

i need a part of a code to understand how make this with mpasm

 

[bananasiong]

I think the datasheet states clear enough.
Set DDRAM address, CGRAM address and followed by CGRAM data.

 

[Nigel Goodwin]

Read the EPE LCD articles mentioned on my site.

 

[ady689]

i dont understand very good, practicaly can you give me an concrete example?

 

[Nigel Goodwin]

i dont understand very good, practicaly can you give me an concrete example?

I've never had reason to do it, but the EPE articles explain exactly what you need to do - writing the code should be trivial?.

 

[ady689]

this is the problem, idont known how to write this in mpasm

 

[Nigel Goodwin]

If you can't write anything, how do you expect to do anything at all with a PIC?.

 

[bananasiong]

I've never had reason to do it, but the EPE articles explain exactly what you need to do - writing the code should be trivial?.

Here they are:
https://www.electronics-lab.com/forum/index.php?topic=12543.0

 

[ericgibbs]

i dont understand very good, practicaly can you give me an concrete example?

hi,
Attached is a Oshonsoft Basic program and its asm listing output.
You should be able to figure out how defined characters are created and used.

Hope this helps.

EDITED: its best to download the *.asm to view off line, else there is no formatting!

 

[Gordz]

It goes like this,

MOVLW B'01000000' ;USER GRAPHIC 0
CALL COMMAND ;SENT TO LCD AS COMMAND
MOVLW B'00000000' ;PIXEL DATA 1 OF 7
CALL DISPLAY ;SENT TO LCD AS DATA

Then to actualy print the user graphic

MOVLW .0 ;USER GRAPHIC POINTER
CALL DISPLAY ;SENT TO LCD AS DATA