lcd
I've seen microcontrollers which claim to drive LCD segments.
For example, the CC430 can drive 96 segments. But, it's a 64 pin chip.
So, it must be providing signals for some kind of mux, what is this interface called?
For dot matrix LCDs, could a microcontroller like this drive more than 96 segments by scanning? I want to drive a small (eg. 32×32 pixel display).
This LCD assembly works with serial commands and is only about $35 [USD]. There are other options as well, but even once you get past the command set, interfacing to small LCDs physically is difficult due to the FPC connectors they use. If that is not a problem, you might find more variety with low cost color displays from Newhaven Display International. I've used two of their products so far. Digikey carries some of them, but some seem to have a large minimum order quantity, so you might have to order directly from newhaven.
The problem with using a microcontroller to drive an LCD is that an LCD requires constant attention. This can be mitigated with a CPLD driven over SPI (using DMA, of course), but then you run into the other problem: Color LCDs require a lot of data. 320x240 in black and white is marginal at 9.6KB, but make it 24 bit color and suddenly you need to deliver 230KB of data in 1/60th of a second. (Don't forget, though, that you can get 4-bit, 16-color control just by tieing the low 20 bits to one setting). A 24-bit frame buffer no longer fits in onboard RAM on most microcontrollers, and you probably don't have time to read from an external RAM chip, clock the data out, and still do other processing. Trying to do this with a CPLD (or an FPGA) and a RAM chip gets you well over the $2 price that caused you to balk in your question.
The traditional solution to interfacing a microcontroller with a color LCD is a display controller like an SSD1963. Here's a very simple block diagram:
Parallel input to a big RAM frame buffer (Translation: More than $2) interfaced with a register-configurable parallel LCD interface. The parallel input is usually compatible with a memory bus interface.
The color LCD market is not always easy to find on the web, usually being the domain of OEMs only, with the rest buying displays from companies who integrate the controller with the display. The best resource I've found has been Crystal Fontz, specifically this page on choosing graphic LCDs. Scroll to the bottom for the controllers, which include the following options (note: Not all are color controllers):
Best Answer
Microcontrollers that drive LCDs are typically for driving segmented LCD with very few segments. They are typically made of custom LCD glass and how the display is multiplexed is built into the LCD glass itself. You will need to check with the display vendor to determine how many common and segment lines there are for your LCD and how they are wired. For a dot matrix LCD you will probably need an external LCD controller. The LCD display vendor can probably recommend one.
For some background in how a on-chip LCD module works.
Microchip application note AN658
EDIT: NXP Has a number of LCD segment drivers available and application notes explaining how to use them. I have not seen a microcontroller that has a built in LCD driver for more than a few segments and certainly not 1024. I'd recommend something like the PCF8576C. You can cascade multiple chips together to drive more segments.