Driving a little LCD

[Eeyore]

Paul Burke wrote:

Eeyore wrote:

TI has one of the MSP430s that could be purpose made for this app too. Shame I'm
not familiar with them.

Get familiar, free up your brain from juggling with memory spaces and
pointer snafus.

The PL/M compiler means I never have to consider them anyway.

UARTs and timers are much nicer too. MSPGCC works well,

MSPGCC ?

and doesn't cost a lot, and C will (may?) make porting easier (even if
you've written your app in assembler). The BIG downside is it's 3.6V max
and no 5V compliant IO.

3.6V isn't a problem here in fact. The same applies to the NXP 89LPC part too.

Why would anyone even use assembler these days for this kind of thing ?

Graham

 

[Henry Kiefer]

"Al" <no.spam@wanted.com> schrieb im Newsbeitrag news:no.spam-1A657C.09133506022007@news.verizon.net...
| Buy this serial LCD display, BPI-216, from:
|
| http://www.seetron.com/cgi-local/SoftCart.100.exe/online-store/scstore/c-
| serial_displays.html?L+scstore+vdwc0855+1176439677
|
| It save you a LOT of trouble. I'm using one now.

I can't believe it. There are guys who buy it for that price?
I can sell you serial LCD 2x40 for $15 with EL backlight.

- Henry


--
www.ehydra.dyndns.info

 

[Spehro Pefhany]

On Tue, 06 Feb 2007 06:28:53 +0000, the renowned Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Spehro Pefhany wrote:

On Tue, 06 Feb 2007 05:51:08 +0000, the renowned Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

Graham

Does it really have to be fully static? Why not, say, a triplexed
display?

I was simply going with what I initially found.

If you have some specific ideas, I'm all ears. I'm new to driving LCDs.

Graham

If you use a micro with an on-board controller, you just need to match
the driver to the chip and set it up properly. There's a chunk of RAM
and you just deposit a bitmap of the desired display pattern. There
are flash chips available from TI, Freescale, Microchip and others
that will handle displays with multiple backplanes. Offhand I don't
recall which 8051 variants have this ability, but I'm sure there are
some by now. As the number of backplanes (and the mux ratio)
increases, you save pins for the segment drive, but the on/off
characteristics suffer (for example, the contrast may be poor, vary
from unit-to-unit, shift substantially with temperature or the viewing
angle may not be as good as you would like). A triplexed display is
almost as good as a static with n/3 + 3 pins used rather than n + 1
pins (for n segments) (if the resistor chain isn't on-chip there might
be a couple more pins used).

It's also possible to use an ordinary micro eg. 89S52 to drive even a
muxed display but it uses a whack of passives and would only be
appropriate where volumes are large and assembly costs small.

A 28-pin PIC16F913 is a comparable chip to many 8051 variants, and can
directly drive up to 60 LCD segments, for GBP ~95p in 1K, but feel
free to spend a few days searching for the ideal part. It's probably
out there somewhere.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Al]

In article <45C8174C.7CF7D059@hotmail.com>,
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

Graham

Buy this serial LCD display, BPI-216, from:

http://www.seetron.com/cgi-local/SoftCart.100.exe/online-store/scstore/c-
serial_displays.html?L+scstore+vdwc0855+1176439677

It save you a LOT of trouble. I'm using one now.

Al

 

[John Fields]

On Tue, 06 Feb 2007 05:51:08 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

---
Figure out a slick way to drive that 32nd pin and you can use this:

http://www.national.com/pf/MM/MM5483.html


--
JF

 

[Paul Burke]

Eeyore wrote:

TI has one of the MSP430s that could be purpose made for this app too. Shame I'm
not familiar with them.

Get familiar, free up your brain from juggling with memory spaces and
pointer snafus. UARTs and timers are much nicer too. MSPGCC works well,
and doesn't cost a lot, and C will (may?) make porting easier (even if
you've written your app in assembler). The BIG downside is it's 3.6V max
and no 5V compliant IO.

Paul Burke

 

[Eeyore]

Dave Platt wrote:

Microchip sells a bunch of PIC microcontrollers which are
designed specifically to drive LCDs. Ferexample, their PIC16F913
is a 28-pin part which can drive certain LCD configurations having up
to 60 addressable segments.

Do you know how they do that ? Presumably there's an app note ?

No doubt - they're quite good about providing howto-doit notes.

I would guess that the LCDs in question are generally multiplexed in a
matrixed arrangement, with some fraction being anodes and the rest
cathodes.

I found some info. It's quite intruiging how the multiplexing works. Not as
simple as with LEDS or VFDs by a long shot !

I believe that other micro vendors have similar parts in their stables.

Ideally I'd like to stick with a member of the 8051 family for familiarity.

Philips (now NXP) has always been big in the 8051 architecture. It
looks as if the P89LPC94x family might do what you want - it's an 8051
derivative and a "universal LCD controller" integrated into a 64-pin
multi-chip module. Toughest part may be trying to get samples, if
what I hear about NXP is true.

Thanks, I'll check that one out.

TI has one of the MSP430s that could be purpose made for this app too. Shame I'm
not familiar with them.

Graham

 

[Dave Platt]

Microchip sells a bunch of PIC microcontrollers which are
designed specifically to drive LCDs. Ferexample, their PIC16F913
is a 28-pin part which can drive certain LCD configurations having up
to 60 addressable segments.

Do you know how they do that ? Presumably there's an app note ?

No doubt - they're quite good about providing howto-doit notes.

I would guess that the LCDs in question are generally multiplexed in a
matrixed arrangement, with some fraction being anodes and the rest
cathodes.

I believe that other micro vendors have similar parts in their stables.

Ideally I'd like to stick with a member of the 8051 family for familiarity.

Philips (now NXP) has always been big in the 8051 architecture. It
looks as if the P89LPC94x family might do what you want - it's an 8051
derivative and a "universal LCD controller" integrated into a 64-pin
multi-chip module. Toughest part may be trying to get samples, if
what I hear about NXP is true.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Eeyore]

Dave Platt wrote:

Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:

I was simply going with what I initially found.

If you have some specific ideas, I'm all ears. I'm new to driving LCDs.

Microchip sells a bunch of PIC microcontrollers which are
designed specifically to drive LCDs. Ferexample, their PIC16F913
is a 28-pin part which can drive certain LCD configurations having up
to 60 addressable segments.

Do you know how they do that ? Presumably there's an app note ?

I believe that other micro vendors have similar parts in their stables.

Ideally I'd like to stick with a member of the 8051 family for familiarity.

You might be able to use an LCD-capable micro of this sort as your
primary programmable device... or, use one as a display-management
peripheral, talking to your main micro over a UART or other serial
interface.

Yes, the thought had crossed my mind although I doubt that would be brilliant
for cost.

Graham

 

[Dave Platt]

In article <45C82025.3B07A17A@hotmail.com>,
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:

I was simply going with what I initially found.

If you have some specific ideas, I'm all ears. I'm new to driving LCDs.

Microchip sells a bunch of PIC microcontrollers which are
designed specifically to drive LCDs. Ferexample, their PIC16F913
is a 28-pin part which can drive certain LCD configurations having up
to 60 addressable segments.

I believe that other micro vendors have similar parts in their stables.

You might be able to use an LCD-capable micro of this sort as your
primary programmable device... or, use one as a display-management
peripheral, talking to your main micro over a UART or other serial
interface.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Eeyore]

Spehro Pefhany wrote:

On Tue, 06 Feb 2007 05:51:08 +0000, the renowned Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

Graham

Does it really have to be fully static? Why not, say, a triplexed
display?

I was simply going with what I initially found.

If you have some specific ideas, I'm all ears. I'm new to driving LCDs.

Graham

 

[Spehro Pefhany]

On Tue, 06 Feb 2007 05:51:08 +0000, the renowned Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

Graham

Does it really have to be fully static? Why not, say, a triplexed
display?


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Eeyore]

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

Graham

 

[Rich Grise]

On Tue, 06 Feb 2007 07:11:57 +0000, Eeyore wrote:

Dave Platt wrote:
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:

I was simply going with what I initially found.
If you have some specific ideas, I'm all ears. I'm new to driving LCDs.

Microchip sells a bunch of PIC microcontrollers which are
designed specifically to drive LCDs. Ferexample, their PIC16F913
is a 28-pin part which can drive certain LCD configurations having up
to 60 addressable segments.

Do you know how they do that ? Presumably there's an app note ?

I believe that other micro vendors have similar parts in their stables.

Ideally I'd like to stick with a member of the 8051 family for familiarity.

Do they still make the 8748? As far as I remember, it was like an

8035/8051 core, but with the I/O ports optimized for use as a peripheral.
I made a big FIFO once using one to interface to a strip chart recorder.

Or, shop around for one with a built-in controller - that's probably
what I'd do in this case.

Good Luck!
Rich

 

[Joel Kolstad]

"Rich Grise" <rich@example.net> wrote in message
newsan.2007.02.06.17.59.07.472211@example.net...

Do they still make the 8748? As far as I remember, it was like an
8035/8051 core, but with the I/O ports optimized for use as a peripheral.

Sorry, the 8748 is the 8048 with a built-in EPROM. Its CPU core is
*significantly* less capable than the 8031's... it doesn't even have a
subtract instruction! (Or a compare instruction for that matter.) I used one
in a couple of projects over a decade ago, now, and became quite good as, "add
a,#256-32 ;Subtract 32 from a")...

 

[John Fields]

On Tue, 06 Feb 2007 08:08:14 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 06 Feb 2007 05:51:08 +0000, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

---
Figure out a slick way to drive that 32nd pin and you can use this:

http://www.national.com/pf/MM/MM5483.html

---
It just hit me that if you've got 32 pins and you weren't excluding
the backplane, then the MM5483 will do just what you need.

Which display are you planning to use?


--
JF

 

[Eeyore]

John Fields wrote:

On Tue, 06 Feb 2007 08:08:14 -0600, John Fields
jfields@austininstruments.com> wrote:

On Tue, 06 Feb 2007 05:51:08 +0000, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Any suggestions for a cheap and cheerful controller chip ? Or is it cheaper to
get a display with integrated driver straight off ?

---
Figure out a slick way to drive that 32nd pin and you can use this:

http://www.national.com/pf/MM/MM5483.html

---
It just hit me that if you've got 32 pins and you weren't excluding
the backplane, then the MM5483 will do just what you need.

Which display are you planning to use?

Just as a 'first off' that I can easily get from Farnell I'm looking at the VI-402
from Trident Microsytems. I'm sure it'll be a widely '2nd sourced' part. In fact I'm
sure Trident will just buy it in to distribute.

Graham

 

On Feb 6, 12:51 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

I've got a low cost application where I want to drive a small LCD ( probably 4
digit ) from a microcontroller.

I looked at the data on the 'bare glass' and there are 32 pins needing driving
which doesn't leave enough for my other I/O.

Use an Atmel AVR - ATmega169P. Get yourself a $20 Butterfly board
(which has an LCD on it) and experiment.

The chip itself is very cheap in large volume, and has almost anything
you could have wanted in an 8051.