displaylcdled
What characteristics of the Pixel Qi display make it visible under daylight conditions?
It seems to have something to do with "daylight grayscale". But what exactly does "daylight grayscale" mean? Is it something that can be accomplished/reproduced in software on any grayscale displays? Can it be reproduced on a color display?
The SED controllers and the KS controllers are the most common graphical LCD controllers. For smaller LCD sizes they often include the drivers, memory, and controller, so a single chip can do everything. They are popular enough that they are being cloned by other manufacturers, so the command sets for some chips very closely relate to one of these two.
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
The pixels are "transflective", meaning half-backlit and half-mirrored.