> >So, what are you guys using now? >never saw the question been raised, >or you all have never being bothered >by charging battery? Well, I did it, but I used an AVR. :) Tiny-26 running from internal 8 MHz R/C clock, PLL'd up to 64 MHz internally to run the buck switch regulator PWM at 500kHz with good resolution. After that, there's a bunch of things you need to know about NIMH cells, you can look at the Panasonic and Sanyo data sheets, and the Cadex docs, plus the Galaxy power docs, and get there. There are temperature limits, lockouts on certain trip conditions... A lot to consider. BTW: The max chips all provide rather a lot of trickle charge for NIMH cells. Some NIMH can't tolerate ANY trickle, some are almost like Nicads. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist