Where to find LCM / system design info?

[A. Nonymous]

Hey guys,

I'm looking to learn about ways to program a monochrome graphical liquid
crystal module (128 x 128 or 128 x 96).

Can anyone suggest some resources to go read about using microprocessors /
asics / fpgas to accomplish such a task?

Thanks!

 

[A. Nonymous]

Ok I should point out that I am looking to eventually package this in a
very small package, something on the order of the size of a beeper or
smaller. Size is very important.

Thanks for any advice you can give...

 

[Spehro Pefhany]

Hey guys,

I'm looking to learn about ways to program a monochrome graphical liquid
crystal module (128 x 128 or 128 x 96).

Can anyone suggest some resources to go read about using microprocessors /
asics / fpgas to accomplish such a task?

Thanks!

It you're using a module with controller, try a google on the
controller chip part number for code examples to do your basic
graphics functions. Eg. (Toshiba) T6963, SED1520, KS(mumble) . There
are only a few common controller types for the graphic modules. Some
ARM microprocessor (almost microcontrollers, just missing the code
memory) chips have *built-in* controllers that work with displays that
have just drivers and no controller. A suitably programmed FPGA can
also be used with that kind of display. You have to spit out data
continuously at a fairly high rate to that kind of display, so it's
unlikely to be very attractive to try and do it in firmware.


Best regards,
Spehro Pefhany

 

[A. Nonymous]

Spehro,

Thank you very much for your reply.

Your last comment seems to be directing me towards a microprocessor
specifically? (Forgive the novice question - I am an EE, I'm just a bit
out of my comfort zone right now)

My concern is cost - I can deal with relatively high non-recurring costs
associated with design and development, but long term I need a very
inexpensive solution for reproducing with high volume.

(No I'm not intending to design this on my own - I am just looking to
become knowledgeable so I know what my challenges will be, before I run
into them with an actual developer.)

My absolute key characteristics are low cost and small size - not always
achievable, but that is why I am doing research now to see what is
available out there.

Thanks again

Joe

 

[[email protected]]

My concern is cost - I can deal with relatively high non-recurring costs
associated with design and development, but long term I need a very
inexpensive solution for reproducing with high volume.

You need to look at microcontrollers sold into the toy market. I'm
assuming this is a monochrome application.

 

[Spehro Pefhany]

Spehro,

Thank you very much for your reply.

Your last comment seems to be directing me towards a microprocessor
specifically? (Forgive the novice question - I am an EE, I'm just a bit
out of my comfort zone right now)

I don't know nearly enough about your application to direct you, so I
have suggested several options that seemed likely from your first
post. There are many other possible ways to go in addition to those
I've mentioned.

My concern is cost - I can deal with relatively high non-recurring costs
associated with design and development, but long term I need a very
inexpensive solution for reproducing with high volume.

Understood. I can tell you that the modules with controllers tend to
be relatively expensive (more like tens of dollars rather than
dollars) in moderate and low volume, mostly because they are not
really used in high volume consumer products. If you really have high
volume, the problem becomes more difficult because there are more
options. You can easily find monochrome LCD displays that cost more
than a complete Gameboy Advance.

(No I'm not intending to design this on my own - I am just looking to
become knowledgeable so I know what my challenges will be, before I run
into them with an actual developer.)

My absolute key characteristics are low cost and small size - not always
achievable, but that is why I am doing research now to see what is
available out there.


Thanks again

No problem.


Best regards,
Spehro Pefhany

 

[A. Nonymous]

Brilliant!

Yes - monochrome.

Unfortunately it is a challenge to search for "toy" and "microcontroller"
(and "lcd") and come up with precisely some of the parts families that may
take care of me. (Not that I need the exact part - I just need to find out
what is out there, sizes, and some reasonable idea of costs)

I will be making good use of google. . .

Thanks!



[email protected] wrote in @g44g2000cwa.googlegroups.com:

 

[[email protected]]

Unfortunately it is a challenge to search for "toy" and "microcontroller"
(and "lcd") and come up with precisely some of the parts families that may
take care of me. (Not that I need the exact part - I just need to find out

Start by looking at the following three companies (not necessarily in
this order):

Winbond
Sunplus
Sonix

Sunplus in particular makes chips used in very cheap PDAs and similar
devices.

 

[A. Nonymous]

Thanks for the hint...

I have heard of Winbond in the past - and may have visited websites of
Sunplus and Sonix in the last couple of days while researching LCM's and
such.

This helps a great deal. Thanks again.


[email protected] wrote in

 

[Joerg]

Hello Spehro,

Understood. I can tell you that the modules with controllers tend to
be relatively expensive (more like tens of dollars rather than
dollars) in moderate and low volume, mostly because they are not
really used in high volume consumer products. If you really have high
volume, the problem becomes more difficult because there are more
options. You can easily find monochrome LCD displays that cost more
than a complete Gameboy Advance.

IOW you can't really use an ordinary micro controller with a cheap
graphics LCD? I mean a low pixel version like the OP suggested.

The driver in firmware is no easy feat but the number of available pins
on a micro seems to be the limiting factor w/o an LCD controller if I
understood you correctly.

Regards, Joerg

 

[Joerg]

Hello Lewin,

Start by looking at the following three companies (not necessarily in
this order):

Winbond
Sunplus
Sonix

Sunplus in particular makes chips used in very cheap PDAs and similar
devices.

The OP just needs to be aware that chips for that market segment (toys
etc.) are, well, bare chips. Gold bump, bare die. Not in a package with
pins and all. It's ok for production but prototyping on a bench can be
quite a challenge.

Regards, Joerg

 

[Spehro Pefhany]

Hello Spehro,


IOW you can't really use an ordinary micro controller with a cheap
graphics LCD? I mean a low pixel version like the OP suggested.

Required bit rates to serial drivers are pretty high, and there are
tight timing constraints. Say the refresh rate is 60Hz and there are
256 x 128 dots.. that's 2MHz/500KHz for bit/nibble-serial plus more
bandwidth for the row driver data). And 4K bytes of RAM, minimum,
which is more than most cheap micros have on board, total. In the
standard T6963 configuration, it takes 8 LSI chips to drive a 64 x 320
monochrome graphic display-- 4 T6A39 column drivers, 1 T6A40 row
driver, two SRAM chips and the controller itself.

The driver in firmware is no easy feat but the number of available pins
on a micro seems to be the limiting factor w/o an LCD controller if I
understood you correctly.

Serial (more or less) so the pin count is probably not an issue unless
you need a load of pins to interface to external RAM.


Best regards,
Spehro Pefhany

 

[Spehro Pefhany]

The OP just needs to be aware that chips for that market segment (toys
etc.) are, well, bare chips. Gold bump, bare die. Not in a package with
pins and all. It's ok for production but prototyping on a bench can be
quite a challenge.

Not to worry, as they are virtually assured to be mask-programed with
a 50K piece or more minimum order. A fine time with arcane emulators,
buggy development systems and Chinglish data (and many pots of coffee)
is surely in the offing.


Best regards,
Spehro Pefhany

 

[[email protected]]

The OP just needs to be aware that chips for that market segment (toys

etc.) are, well, bare chips. Gold bump, bare die. Not in a package with

All these COB micros are available as ROMless bodies either in standard
IC packaging or on small demo boards (typically 1"x1") bonded out and
ready to use. If he establishes the contacts to buy the chips, he will
have access to the prototyping boards.

 

[Joerg]

Hello Lewin,

All these COB micros are available as ROMless bodies either in standard
IC packaging or on small demo boards (typically 1"x1") bonded out and
ready to use. If he establishes the contacts to buy the chips, he will
have access to the prototyping boards.

I meant LCD drivers such as the ones from Sunplus. Probably you can have
them packaged somewhere though.

Regards, Joerg

 

[Joerg]

Hello Spehro,

Required bit rates to serial drivers are pretty high, and there are
tight timing constraints. Say the refresh rate is 60Hz and there are
256 x 128 dots.. that's 2MHz/500KHz for bit/nibble-serial plus more
bandwidth for the row driver data). And 4K bytes of RAM, minimum,
which is more than most cheap micros have on board, total. In the
standard T6963 configuration, it takes 8 LSI chips to drive a 64 x 320
monochrome graphic display-- 4 T6A39 column drivers, 1 T6A40 row
driver, two SRAM chips and the controller itself.

That is unfortunate especially since most applications do not require a
fast change of the displayed information. I may have an application
coming up where a small low-res display would be just the ticket. But
only if an ordinary (meaning cheap) uC can handle it on the side. The
LCD wouldn't have to do much more than an etch-a-sketch, and about at
that speed.

Serial (more or less) so the pin count is probably not an issue unless
you need a load of pins to interface to external RAM.

But aren't you back to the expensive kind of LCD with a controller that
can take serial data?

I wonder if there is a toy game, maybe yahtzee or a watch, that is
really cheap and offers a way to send data to its LCD. Then the parts
list of a new unit might contain a part with a Walmart P/N ;-)

Sometimes it is amazing how cheap things get. There was a radio with ear
phones and all recently. It even had an FM synthesizer. Sold for 99c and
you could buy unlimited qties. The RF performance was lousy though.

Regards, Joerg