Thanks to all for the suggestions.

Turns out, when I bothered to simulate it, I just had a standard jump table
bug. The table lookup for the row data ended up setting PCLATH, but I didn't
reset it for the next jump to lookup the character beeing defined. So the
character definition code only defined the top line of the first character
before jumping back to org 0 again. Doh!

If anyone is interested, I could post the working code.

Andy

-----Original Message-----
From: Steve Lawther [mailto:SLawther@HUSKY.CO.UK]
Sent: 21 February 2000 10:11
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: Custom LCD Characters


Andy,

The pseudo code looks fine - When you display a user character afterwards,
 is it blank, random, or has it a pattern to it?

Does your code check the busy bit from the display, or wait the maximum
amount of time in-between writes?

Steve Lawther

> -----Original Message-----
> From: Andy Baker [SMTP:AB@DATCON.CO.UK]
> Sent: Monday, February 21, 2000 9:51 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Custom LCD Characters
>
> Hi all,
>
> My current project is a pre-amplifier, where a PIC (16F84) is used to
> control the switching of the inputs, and to display on an LCD what you are
> listening to. This is all working fine.
>
> For an enhancement, I need some underlined characters for the display, so
> set about using the CGRAM feature of the 44870 -style LCD. Trouble is, it
> doesn't work. I don't have code here with me, but the the gist of what I'm
> doing is below. Anything obvious spring to mind as wrong. I'll post code
> tomorrow if I can.
>
> Alternatively, anyone got any working code I can compare mine against to
> spot the bug?
>
> Thanks,
>
> Andy
>
> Immediately after LCD initialisation, This is what I do:
>
> Set CGRam address (instruction 0x40 sent using known working LCD command
> fucntion)
> For Character = 0 to 7
> For Row = 0 to 7
> Lookup (Character , Row) in table to get data byte
> Write data byte to LCD using known working LCD data write function)
> Endfor
> Endfor
>
>
--------------------
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