lcd4linux-users

[lcd4linux] Re: Everbouquet 44780 modules

[Michael R. <re...@eu...>]

Hi Aragon,

try to post such questions to the list!

> On a completely different thread, I was wondering if any of your 44780
> modules you had were made by Everbouquet/Wayton?  Their part numbers
> resemble MC1608, MC2004, MC4002, MC4004, etc.

No, I'm afraid I have none of such a kind.

> The reason I'm asking is because I have one, and I can't help but notice
> some of the unused circuitry on it.  There are pads for a transistor and a
> bunch of resistors which looks unmistakebly like a switching circuit
> attached to the LED backlight Anode.  The base of the transistor pads leads
> through a resistor pad into one of the controller chips.
> 
> I'm thinking that perhaps these modules have an undocumented 44780 command
> to toggle the backlight on and off, maybe even to adjust its intensity too. 
> I've tried mailing them asking this, but so far no luck with useful replies. 

Can you tell what controller pin is connected to this transistor? I 
could search through my various datasheets to find an answer...


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
Geisslergasse 4                                   Fax: +43 316  692343
A-8045 Graz, Austria                          e-mail: re...@eu...

[lcd4linux] Re: Everbouquet 44780 modules

[Aragon G. <ar...@ph...>]

| By Michael Reinelt <re...@eu...>
|                                          [ 2004-02-16 10:10 +0200 ]
> try to post such questions to the list!

Okay ;)


> >The reason I'm asking is because I have one, and I can't help but notice
> >some of the unused circuitry on it.  There are pads for a transistor and a
> >bunch of resistors which looks unmistakebly like a switching circuit
> >attached to the LED backlight Anode.  The base of the transistor pads leads
> >through a resistor pad into one of the controller chips.
> >
> >I'm thinking that perhaps these modules have an undocumented 44780 command
> >to toggle the backlight on and off, maybe even to adjust its intensity 
> >too. I've tried mailing them asking this, but so far no luck with useful 
> >replies. 
> 
> Can you tell what controller pin is connected to this transistor? I 
> could search through my various datasheets to find an answer...

I'll try take a photo of it tonight.

I can trace the track going into one of the silicon chips embedded on the
controller board, but that's it.  It also jumps through to the otherside of
the board, but can't trace it there (without breaking my module).

Before I went to bed last night I checked the voltage between the base pad
and ground - ~2.7V before 44780 initialisation, ~2.5V after initialisation.

I'm going to hack up someone's source code tonight hopefully and see what
happens if I play with the two "unused" bits (D1 and D0) of the Set
Interface Length and Move Cursor commands. ;)


Regards,
Aragon

Re: [lcd4linux] Re: Everbouquet 44780 modules

[Aragon G. <ar...@ph...>]

| By Aragon Gouveia <ar...@ph...>
|                                          [ 2004-02-16 10:29 +0200 ]
> > >The reason I'm asking is because I have one, and I can't help but notice
> > >some of the unused circuitry on it.  There are pads for a transistor and a
> > >bunch of resistors which looks unmistakebly like a switching circuit
> > >attached to the LED backlight Anode.  The base of the transistor pads leads
> > >through a resistor pad into one of the controller chips.
> > >
> > >I'm thinking that perhaps these modules have an undocumented 44780 command
> > >to toggle the backlight on and off, maybe even to adjust its intensity 
> > >too. I've tried mailing them asking this, but so far no luck with useful 
> > >replies. 

Whoops, I cut off the first part without thinking.

This is in reference to 44780 modules manufactured by Everbouquet/Wayton. 
Their part numbers resemble MC1602, MC2002, MC2004, MC4004, etc.  If you
have one, read above. :)


Regards,
Aragon

Re: [lcd4linux] Re: Everbouquet 44780 modules

[Aragon G. <ar...@ph...>]

A high quality photo of my module's controller board is available at:

http://decoder.geek.sh/misc/mc2004E.jpg

The interesting component pads are:

R11
Q1
R9
R10

The leftmost pad of Q1 leads through R11 and then into one of the 44780
chips.  This must be the base.  Voltage between that line and ground is
about 2.5V after 44780 initialisation.

The topmost pad of Q1 connects to pin15 on the connector (LED+).

The rightmost pad of Q1 connects to the LED Anode via R9/R10.

The jumper on R7 would need to be desoldered before attaching this extra
circuitry.  If R7 is left in place, the backlight will come on and stay on
whenever power is applied to LED+.

With the extra circuitry in place and R7 removed, the backlight will only
come on when Q1's output is HIGH, and LED+ has power.

Now the question is.. how do you tell the 44780 to set Q1 high!?

So far I've tried sending this data in instruction mode (RS low):

  1xx11
  1xx01
  1xx10

and:

  1xxx11

  x = appropriate value for my interface/cursor settings


No luck.  Voltage at R11 stays 2.5V.

Any ideas? :)


Regards,
Aragon


| By Aragon Gouveia <ar...@ph...>
|                                          [ 2004-02-16 10:29 +0200 ]
> I'll try take a photo of it tonight.
> 
> I can trace the track going into one of the silicon chips embedded on the
> controller board, but that's it.  It also jumps through to the otherside of
> the board, but can't trace it there (without breaking my module).
> 
> Before I went to bed last night I checked the voltage between the base pad
> and ground - ~2.7V before 44780 initialisation, ~2.5V after initialisation.
> 
> I'm going to hack up someone's source code tonight hopefully and see what
> happens if I play with the two "unused" bits (D1 and D0) of the Set
> Interface Length and Move Cursor commands. ;)

Re: [lcd4linux] Re: Everbouquet 44780 modules

[Michael R. <re...@eu...>]

Hi Aragon,

> A high quality photo of my module's controller board is available at:
> http://decoder.geek.sh/misc/mc2004E.jpg
Hey! This is really high quality! How did you do this?

> The leftmost pad of Q1 leads through R11 and then into one of the 44780
> chips.  This must be the base.  Voltage between that line and ground is
> about 2.5V after 44780 initialisation.

Hmm... finding out which pin this is connected to will be impossible, 
because of these 'blobs'. Maybe you can figure out two neighbour pins, 
which lead to the external connector, and where you know the meaning.

I see there are three chips on your display. Two of them are HD44780. 
What's the third? How can you be shure that the middle one, where your 
R11 is connected to, is a HD44780, and not something completely 
different? (Maybe something like a LCD column driver?)


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
Geisslergasse 4                                   Fax: +43 316  692343
A-8045 Graz, Austria                          e-mail: re...@eu...

Re: [lcd4linux] Re: Everbouquet 44780 modules

[Aragon G. <ar...@ph...>]

Howdy

| By Michael Reinelt <re...@eu...>
|                                          [ 2004-02-16 21:15 +0200 ]
> >A high quality photo of my module's controller board is available at:
> >http://decoder.geek.sh/misc/mc2004E.jpg
> Hey! This is really high quality! How did you do this?

Canon Powershot S330 :)


> I see there are three chips on your display. Two of them are HD44780. 
> What's the third? How can you be shure that the middle one, where your 
> R11 is connected to, is a HD44780, and not something completely 
> different? (Maybe something like a LCD column driver?)

I'm not sure what any of the blobs are, but all the I/O tracks lead into
the left most blob.  If I were to destroy my module I could remove the LCD
from the board and trace the tracks on the other side, but I'm not sure I'm
keen to do that.  It probably won't help, and if it did, probably won't be
worth it.

I guess my only hope is to try get an answer out of the manufacturer.  I'm
considering making a distance call to them.  Emailing them has brought no
useful response so far.

Thanks for looking :)


Regards,
Aragon

Re: [lcd4linux] Re: Everbouquet 44780 modules

[Michael R. <re...@eu...>]

Hi Aragon,

>>I see there are three chips on your display. Two of them are HD44780. 
>>What's the third? How can you be shure that the middle one, where your 
>>R11 is connected to, is a HD44780, and not something completely 
>>different? (Maybe something like a LCD column driver?)

> I'm not sure what any of the blobs are, but all the I/O tracks lead into
> the left most blob.  If I were to destroy my module I could remove the LCD
> from the board and trace the tracks on the other side, but I'm not sure I'm
> keen to do that.  It probably won't help, and if it did, probably won't be
> worth it.

This is not a big problem - i have done this several times: Just move 
the clamps which hold the metal frame. On the other side you will find 
the display glass and two stripes of conducting rubber.

The only important thing when reassembling is to find the correct 
position. Try it out before fixing the clamps :-)


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
Geisslergasse 4                                   Fax: +43 316  692343
A-8045 Graz, Austria                          e-mail: re...@eu...