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'How to load CGRAM in Optrex Modules (H44780)'
1999\04\30@125039 by Craig Lee

In the Optrex data book:

"CGRAM...which memorize characters that you can freely input by program."


5x7 characters would require at least 35 bits of information, and the data
book has no protocol information on how to do this.


1999\04\30@131519 by ARudzki

Set your RS and R/W lines low, and write a 0x40 to the module.and toggle E.
This will place the data pointer to
point to CG memory (location 0) instead of display memory.

Start writing your data 8 bytes of 8 bits (only the 5 least significant
display) per character.  When you are done, write an 0x80 to the display,
and your cursor will home in display memory.

To use the characters, they will be characters 0-7,  so if you redefine the
first character to be an up arrow and want to print an up arrow, use 'print
chr$(0)'  << this is BASIC

Hope this helps


1999\04\30@132313 by Kevin Fisk

Check out this link:
Lots of LCD info.



Craig Lee wrote:
{Quote hidden}

1999\04\30@132316 by Adam Bryant

picon face
Check out Myke Predko's web site at  He has recently added
a section about how to define your own characters.

On Fri, 30 Apr 1999 10:51:13 -0600 Craig Lee <spam_OUTcleeTakeThisOuTspamATTCANADA.NET> writes:
{Quote hidden}

Adam Bryant (age 0x23) (work) (home)
Parker, CO, USA
Robotics, RC Airplanes, anything using a PIC

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1999\04\30@172207 by paulb

ARudzki wrote:

> Set your RS and R/W lines low, and write a 0x40 to the module and
> toggle E.
> This will place the data pointer to point to CG memory (location 0)
> instead of display memory.

  Description a little bit fuzzy there, sorry!

 Writing (R/~W low) with RS low, writes a *command* while writing with
RS high writes *data*, as when you send ASCII to the display.

 You first write a "Set CGRAM Address" *command*, then write all your
*data* bytes in sequence.

 You then write a command to set the cursor position and the controller
will thereafter accept further data writes as ASCII characters to be
displayed including the new characters you have defined.

 Not comprehensive, but I hope a little clearer.
       Paul B.

1999\04\30@191156 by Eric Schlaepfer

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Hi Craig,

>In the Optrex data book:

First problem. Read the HD44780 data sheet instead, available off the
Hitachi web site:



1999\04\30@192036 by wagnerl

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take a look at: with a 8051 example,

1999\04\30@205448 by Myke Predko

Hi Craig,

Just to follow up on this.

1.  You can get the information to do this from my LCD page as Adam pointed

2.  I have been writing a couple of articles on the Hitatchi 44780
controller for LCDs for Bruce Reynold's "Rentron" site.  You should look at:

I think this will have what you are looking for.

Good luck and let me know if you have any questions,

{Original Message removed}

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