Quoting Peter Feucht : > Hi, > > I have a very small project on my desk: A tone generator which should > produce a simple meldody, has to check a key press and light 2 LEDs. No deal > at all BUT cost is a major factor. When checking the prices I found, that > the voltage regulator's price is in about the same region as the PIC itself, > which lead me to the question: Are there any micro controllers which can be > operated directly at an unregulated 12V supply? > > Thanks for enlighten me and best regards > > Peter Assume we`re talking high volume a 78L05 can be had for a nickel or so (EUR 0.035), but if you want to operate *reliably* from an automotive supply more protection will be required due to the various transients you should expect on an automotive power bus (see the appropriate standard for the voltages +- and energies and durations you can expect). The PIC16HV540 series has an internal regulator (which would require external parts for it to survive reliably in an automotive environment), but I don`t think it`s necessarily cost-effective (the parts without the regulator and the icky 12-bit instruction set are very cheap), with zeners costing pennies each. A shunt regulator (zener or TVS) can provide semi-regulated power that is pretty much bulletproof. And semi-regulated power is usually good enough. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist