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 AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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.
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 AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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.
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
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")...
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.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.