Mungo Henning wrote: > The volume isn't great (and I don't want to drive it in 'bridge' mode), hence > I need some amplification which will feed a reasonable-sized speaker Why not use an LM386 - it will deliver 300mW or so into 8ohms with a 6V supply. There is also the LM4880 - a dual audio amp in an 8 pin package with a shutdown input (<1uA in shutdown mode). It will deliver over 300mW per channel on a 5V supply. You can get data on these from National Semiconductor's Web site - www.national.com. To generate sounds other than square waves, the easiest way is to do a pulse-width-modulation technique, but this requires producing a pulse train at a rate several times your desired maximum output frequency. -- Clyde Smith-Stubbs | HI-TECH Software, | Voice: +61 7 3300 5011 clyde@hitech.com.au | P.O. Box 103, Alderley, | Fax: +61 7 3300 5246 http://www.hitech.com.au | QLD, 4051, AUSTRALIA. | BBS: +61 7 3300 5235 ---------------------------------------------------------------------------- For info on the World's best C cross compilers for embedded systems, point your WWW browser at http://www.hitech.com.au, or email info@hitech.com.au