Years ago I built a discrete-logic digital dimmer that broke the half cycle into 256 linear steps. I seem to remember being able to easily see the changes near the low end of the table. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) ----- Original Message ----- From: "Spehro Pefhany" To: Sent: Sunday, September 16, 2001 7:01 PM Subject: Re: [EE]: Lamp S-Curve Table > At 08:54 AM 9/17/01 +1000, you wrote: > > >My current code has a 64 byte table. (not coded by me) > >You can see the stepping at the low end of it mainly. > >Maybe the table values are wrong & 64 steps are enough. > >DMX & other standards use all 256 levels although I guess > >it's up to the dimmer designer whether to actually implement > >all 256 steps. I imagine some just shift the input byte a few > >bits towards LSB and use a smaller table. > > You may be able to improve things by doing linear interpolation > on your table. And on the mid-range "F" PICs you get 14 bits > on the output of the table for free. > > Best regards, > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- = > Spehro Pefhany --"it's the network..." "The Journey is the reward" > speff@interlog.com Info for manufacturers: http://www.trexon.com > Embedded software/hardware/analog Info for designers: http://www.speff.com > Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- = > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.