Re: AW: [avr-chat] LCD duty cycles, help please

[James Dessart]

On Sun, 27 Feb 2005 20:02:43 +0100, Flemming Gram Christensen
<address@hidden> wrote:
> ST has some application notes for the ST7 and other ST microcontrollers about 
> driving graphic LCDs directly.
> It is not something you will complete in the evening.

The ST app note, unfortunately, only deals with segment-based LCDs.

> Another easier option is to use the mega169 which has the hardware to drive 
> such an display.

Same there, they only drive segments.

The module I've got is a multiplexed device (640x480), with a 4-bit
parallel interface and a shift-clock to move to the next 4 pixels, and
another to shift to the next line. There is one VLCD pin for supply
current, the duty cycle is 1/242 (which I'm still not clear on, is it
1/242 of a second, or 1/242 of the time the pixel is being written
out?) at -13.1V. I've figured out how to generate the negative
voltage, it's just a question of when to activate it or drop it to
zero, what kind of timing I need to have.

Thanks for your help.

James