dev builds
themes manual
device status forums
mailing lists
IRC bugs
dev guide

Rockbox mail archive

Subject: Re: LCD backlight dimming

Re: LCD backlight dimming

From: Linus Nielsen Feltzing <>
Date: Tue, 16 Mar 2004 08:32:10 +0100

roland wrote:
> does somebody know, at which rate the led`s of the display can be
> switched on/off? maybe dimming could be done by switching the display
> on/off very quickly - by software.

On the recorder, the backlight is controlled by the Real Time Clock,
using a square wave output. The square wave can have different
frequencies in 16 discrete steps from 0Hz to 32kHz, but the duty period
can't be changed, it's always a square wave. So we can forget dimming on
the recorder.

On the player, however, the backlight is controlled by a port pin, so
there is a possibility to dim it by toggling the pin. I'm not sure I see
the point in doing so, but some people may find it "cool".

> at least, there have been recorders out there which were able to dim
> (i saw a videoclip somebody posted on this list). do we know that was
> a hardware or a software-based dimming?

Yes, there is a hardware flaw in some recorders, especially FM and V2,
which causes the backlight to dim slowly instead of turning off. I have
not been able to control this behaviour, and certainly not control the
dim rate.

Received on 2004-03-16

Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy