Inverse Video - - LCD Query
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Posts: 46,084
I recently operated a device that appeared to use a 2 X 16 backlit
LCD display. The display mode was inverse video. Very nice effect for
a backlit display. I don't believe the 44780 command set supports
inverse video. Is there some kind of "new and improved" display I
don't know about?
BTW-
This was not a fancy graphics display, seemed to be text only.
Thanks
Rich
LCD display. The display mode was inverse video. Very nice effect for
a backlit display. I don't believe the 44780 command set supports
inverse video. Is there some kind of "new and improved" display I
don't know about?
BTW-
This was not a fancy graphics display, seemed to be text only.
Thanks
Rich
Comments
Most LCD displays support custom defined characters. You could define
characters in inverse.
Like the letter A for example: (character size 5x7 in 8x8 matrix)
Normal Inverse
00000100 11111011
00001010 11110101
00010001 11101110
00011111 11100000
00010001 11101110
00010001 11101110
00010001 11101110
00000000 11111111
Maybe your display has enough ram (eeprom) to store an additional character
set.
(or the charactercodes 128-255 are already defined as inverse characters
0-127).
Then there is no need for an inverse video mode as you can create your own.
Some displays however may have this function.
Greetings peter
Oorspronkelijk bericht
Van: iceninevt@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Y9JlK5VUgsvCb7EGSTsNgnQ-RtrYvWOd88jTewFDB2Jh5P9iyH6uIfz7zH0rI_Zw5TScYeLj5qQu]iceninevt@y...[/url
Verzonden: dinsdag 10 juli 2001 21:06
Aan: basicstamps@yahoogroups.com
Onderwerp: [noparse][[/noparse]basicstamps] Inverse Video - - LCD Query
I recently operated a device that appeared to use a 2 X 16 backlit
LCD display. The display mode was inverse video. Very nice effect for
a backlit display. I don't believe the 44780 command set supports
inverse video. Is there some kind of "new and improved" display I
don't know about?
BTW-
This was not a fancy graphics display, seemed to be text only.
Thanks
Rich
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--- In basicstamps@y..., "Peter Verkaik" <peterverkaik@b...> wrote:
> Hi Rich,
>
> Most LCD displays support custom defined characters. You could
define
> characters in inverse.
> Like the letter A for example: (character size 5x7 in 8x8 matrix)
>
> Normal Inverse
> 00000100 11111011
> 00001010 11110101
> 00010001 11101110
> 00011111 11100000
> 00010001 11101110
> 00010001 11101110
> 00010001 11101110
> 00000000 11111111
>
> Maybe your display has enough ram (eeprom) to store an additional
character
> set.
> (or the charactercodes 128-255 are already defined as inverse
characters
> 0-127).
> Then there is no need for an inverse video mode as you can create
your own.
> Some displays however may have this function.
>
> Greetings peter
>
>
>
>
>
Oorspronkelijk bericht
> Van: iceninevt@y... [noparse][[/noparse]mailto:iceninevt@y...]
> Verzonden: dinsdag 10 juli 2001 21:06
> Aan: basicstamps@y...
> Onderwerp: [noparse][[/noparse]basicstamps] Inverse Video - - LCD Query
>
> I recently operated a device that appeared to use a 2 X 16 backlit
> LCD display. The display mode was inverse video. Very nice effect
for
> a backlit display. I don't believe the 44780 command set supports
> inverse video. Is there some kind of "new and improved" display I
> don't know about?
>
> BTW-
>
> This was not a fancy graphics display, seemed to be text only.
>
> Thanks
>
> Rich
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@y...
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
Thanks for your reply. I've been thinking about this. I don't know
how much of the ascii character set is supported by the typical 44780
display. (Do all 44780 displays share a common character set?) If the
character set in the display ROM supports those characters I am
totally golden. If not, I think I can only cram 8 custom characters
in display ram.
Anyway, I can't wait to get home to play around with this.
Tragically, all my inspiration comes while I should be working.
Best Regards
Rich
--- In basicstamps@y..., "Peter Verkaik" <peterverkaik@b...> wrote:
> Hi Rich,
>
> Most LCD displays support custom defined characters. You could
define
> characters in inverse.
> Like the letter A for example: (character size 5x7 in 8x8 matrix)
>
> Normal Inverse
> 00000100 11111011
> 00001010 11110101
> 00010001 11101110
> 00011111 11100000
> 00010001 11101110
> 00010001 11101110
> 00010001 11101110
> 00000000 11111111
>
> Maybe your display has enough ram (eeprom) to store an additional
character
> set.
> (or the charactercodes 128-255 are already defined as inverse
characters
> 0-127).
> Then there is no need for an inverse video mode as you can create
your own.
> Some displays however may have this function.
>
> Greetings peter
>
>
>
>
>
Oorspronkelijk bericht
> Van: iceninevt@y... [noparse][[/noparse]mailto:iceninevt@y...]
> Verzonden: dinsdag 10 juli 2001 21:06
> Aan: basicstamps@y...
> Onderwerp: [noparse][[/noparse]basicstamps] Inverse Video - - LCD Query
>
> I recently operated a device that appeared to use a 2 X 16 backlit
> LCD display. The display mode was inverse video. Very nice effect
for
> a backlit display. I don't believe the 44780 command set supports
> inverse video. Is there some kind of "new and improved" display I
> don't know about?
>
> BTW-
>
> This was not a fancy graphics display, seemed to be text only.
>
> Thanks
>
> Rich
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@y...
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
Check out http://home.iae.nl/users/pouweha/lcd/lcd.shtml for technical data
about the HD44780 displays.
(also program code)
I overviewed it quickly and it is also possible to write directly to the
display's DDRAM. (display data ram)
So, instead of sending character codes to be displayed you could write
bitmaps to the display.
To display an inverse character would require you to write 8 databytes plus
additional address bytes.
Basically, the display update is slower but allows you to have inverse
video!
Greetings peter
Oorspronkelijk bericht
Van: iceninevt@y... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=VIAR1gP7CIo0Ki0YTJymJV8rGDNb8wSnNSwbKmw9otuOiEzbmbWX1f5DyH_C30tvHlJGoFUuGTayiDd4bQ]iceninevt@y...[/url
Verzonden: dinsdag 10 juli 2001 22:31
Aan: basicstamps@yahoogroups.com
Onderwerp: [noparse][[/noparse]basicstamps] Re: Inverse Video - - LCD Query
Hi Peter
Thanks for your reply. I've been thinking about this. I don't know
how much of the ascii character set is supported by the typical 44780
display. (Do all 44780 displays share a common character set?) If the
character set in the display ROM supports those characters I am
totally golden. If not, I think I can only cram 8 custom characters
in display ram.
Anyway, I can't wait to get home to play around with this.
Tragically, all my inspiration comes while I should be working.
Best Regards
Rich
--- In basicstamps@y..., "Peter Verkaik" <peterverkaik@b...> wrote:
> Hi Rich,
>
> Most LCD displays support custom defined characters. You could
define
> characters in inverse.
> Like the letter A for example: (character size 5x7 in 8x8 matrix)
>
> Normal Inverse
> 00000100 11111011
> 00001010 11110101
> 00010001 11101110
> 00011111 11100000
> 00010001 11101110
> 00010001 11101110
> 00010001 11101110
> 00000000 11111111
>
> Maybe your display has enough ram (eeprom) to store an additional
character
> set.
> (or the charactercodes 128-255 are already defined as inverse
characters
> 0-127).
> Then there is no need for an inverse video mode as you can create
your own.
> Some displays however may have this function.
>
> Greetings peter
>
>
>
>
>
Oorspronkelijk bericht
> Van: iceninevt@y... [noparse][[/noparse]mailto:iceninevt@y...]
> Verzonden: dinsdag 10 juli 2001 21:06
> Aan: basicstamps@y...
> Onderwerp: [noparse][[/noparse]basicstamps] Inverse Video - - LCD Query
>
> I recently operated a device that appeared to use a 2 X 16 backlit
> LCD display. The display mode was inverse video. Very nice effect
for
> a backlit display. I don't believe the 44780 command set supports
> inverse video. Is there some kind of "new and improved" display I
> don't know about?
>
> BTW-
>
> This was not a fancy graphics display, seemed to be text only.
>
> Thanks
>
> Rich
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@y...
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
>
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http://docs.yahoo.com/info/terms/
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I believe it is not necessary to store an inverse character pattern set in
your microcontroller.
You could first display the character normally, then read the DDRAM for the
character bitmap,
inverse the bits, and then write them back to the DDRAM. Makes it even
slower but should work.
Greetings peter
custom characters when using the 5x7 font and four custom characters when
using the 5x10 font. Not enough for a whole character set....
-- Jon Williams
-- Dallas, TX
In a message dated 7/10/01 4:17:14 PM Central Daylight Time,
peterverkaik@b... writes:
> Most LCD displays support custom defined characters. You could define
> characters in inverse.
> Like the letter A for example: (character size 5x7 in 8x8 matrix)
>
> Normal Inverse
> 00000100 11111011
> 00001010 11110101
> 00010001 11101110
> 00011111 11100000
> 00010001 11101110
> 00010001 11101110
> 00010001 11101110
> 00000000 11111111
>
> Maybe your display has enough ram (eeprom) to store an additional character
> set.
>
[noparse][[/noparse]Non-text portions of this message have been removed]
to download custom characters to the CGRAM and display them. These displays
are character based. The DDRAM holds the character (ASCII) code, not the bit
pattern -- that is read from a separate internal ROM or from the CGRAM for
custom characters. You cannot write to individual bits on the screen with a
HD44780-based display. Sorry....
-- Jon Williams
-- Dallas, TX
PS: [noparse][[/noparse]OT] I just returned from my first visit to Holland. You have a really
nice country -- lot's of very friendly people.
In a message dated 7/10/01 7:53:11 PM Central Daylight Time,
peterverkaik@b... writes:
> Check out http://home.iae.nl/users/pouweha/lcd/lcd.shtml for technical data
> about the HD44780 displays.
> (also program code)
>
> I overviewed it quickly and it is also possible to write directly to the
> display's DDRAM. (display data ram)
> So, instead of sending character codes to be displayed you could write
> bitmaps to the display.
> To display an inverse character would require you to write 8 databytes plus
> additional address bytes.
> Basically, the display update is slower but allows you to have inverse
>
[noparse][[/noparse]Non-text portions of this message have been removed]
That's bad luck. Like I said, I overviewed it quickly and, based upon its
name, I assumed the DDRAM
would hold the individual bits for the display. My guess then is that Rich's
display has defined the
inverse video characters into the ROM, presumably in the character range
$A0-$FF (for the normal
characters the range is $20-$7F). This would produce inverse video by adding
$80 to the character code.
But thanks for the info.
Greetings peter
Oorspronkelijk bericht
Van: jonwms@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dJSde8COAib5VppL0enEl7Ap5U6QjfgumXIBWOS_8zReZG8MJF8tjzRvVyemRCfOiDDjCqBlOAV9]jonwms@a...[/url
Verzonden: woensdag 11 juli 2001 02:01
Aan: basicstamps@yahoogroups.com
Onderwerp: Re: [noparse][[/noparse]basicstamps] Re: Inverse Video - - LCD Query
The only way to create custom patterns on a display that uses the HD44780 is
to download custom characters to the CGRAM and display them. These displays
are character based. The DDRAM holds the character (ASCII) code, not the
bit
pattern -- that is read from a separate internal ROM or from the CGRAM for
custom characters. You cannot write to individual bits on the screen with a
HD44780-based display. Sorry....
-- Jon Williams
-- Dallas, TX
PS: [noparse][[/noparse]OT] I just returned from my first visit to Holland. You have a really
nice country -- lot's of very friendly people.
In a message dated 7/10/01 7:53:11 PM Central Daylight Time,
peterverkaik@b... writes:
> Check out http://home.iae.nl/users/pouweha/lcd/lcd.shtml for technical
data
> about the HD44780 displays.
> (also program code)
>
> I overviewed it quickly and it is also possible to write directly to the
> display's DDRAM. (display data ram)
> So, instead of sending character codes to be displayed you could write
> bitmaps to the display.
> To display an inverse character would require you to write 8 databytes
plus
> additional address bytes.
> Basically, the display update is slower but allows you to have inverse
>
[noparse][[/noparse]Non-text portions of this message have been removed]
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characters inverse can't you just reverse the polarised film on the display
and make the display white characters with a black background??
I used to do this with my watch's etc when i was younger and i assume that
the lcd screens still have the film as without it the watch's didnt work..
Just my 2 cents. Hope it helps.
Peter Rogers
Original Message
From: "Peter Verkaik" <peterverkaik@b...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, July 11, 2001 1:11 PM
Subject: RE: [noparse][[/noparse]basicstamps] Re: Inverse Video - - LCD Query
> Hi Jon,
>
> That's bad luck. Like I said, I overviewed it quickly and, based upon its
> name, I assumed the DDRAM
> would hold the individual bits for the display. My guess then is that
Rich's
> display has defined the
> inverse video characters into the ROM, presumably in the character range
> $A0-$FF (for the normal
> characters the range is $20-$7F). This would produce inverse video by
adding
> $80 to the character code.
> But thanks for the info.
>
> Greetings peter
>
>
>
>
Oorspronkelijk bericht
> Van: jonwms@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=xTxEWLesDyj671cl0bEzIp-UtTVOL7Sb7ELiqqLhhXBeAJlagXLjHXnj4q5o9WCXwEemYDa3QkhA]jonwms@a...[/url
> Verzonden: woensdag 11 juli 2001 02:01
> Aan: basicstamps@yahoogroups.com
> Onderwerp: Re: [noparse][[/noparse]basicstamps] Re: Inverse Video - - LCD Query
>
> The only way to create custom patterns on a display that uses the HD44780
is
> to download custom characters to the CGRAM and display them. These
displays
> are character based. The DDRAM holds the character (ASCII) code, not the
> bit
> pattern -- that is read from a separate internal ROM or from the CGRAM for
> custom characters. You cannot write to individual bits on the screen with
a
> HD44780-based display. Sorry....
>
> -- Jon Williams
> -- Dallas, TX
>
> PS: [noparse][[/noparse]OT] I just returned from my first visit to Holland. You have a
really
> nice country -- lot's of very friendly people.
>
>
> In a message dated 7/10/01 7:53:11 PM Central Daylight Time,
> peterverkaik@b... writes:
>
>
> > Check out http://home.iae.nl/users/pouweha/lcd/lcd.shtml for technical
> data
> > about the HD44780 displays.
> > (also program code)
> >
> > I overviewed it quickly and it is also possible to write directly to the
> > display's DDRAM. (display data ram)
> > So, instead of sending character codes to be displayed you could write
> > bitmaps to the display.
> > To display an inverse character would require you to write 8 databytes
> plus
> > additional address bytes.
> > Basically, the display update is slower but allows you to have inverse
> >
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
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>
>