I have seen MUCH worse designs than the PICKIT2 from Microchip. There are some appalling appnotes still in Microchip's inventory. Personally, I always use some form of spike protection on open, exposed conductors like this, to prevent damage. I use higher-voltage devices on sensitive circuits like PGD and PGC, because the low-voltage ones add a lot of capacitance to the pin. You need to always assume that Microchip is primarily in the business to sell CHIPS, not test equipment, or prototype circuits. REMEMBER: YOU are the engineer, and if you design in a hazard, YOU will be sued, not Microchip (or anybody else, for that matter). --Bob A On 7/14/08, Tamas Rudnai wrote: > Actually it is interesting that the PicKit2 design exploits the behaviour > of > the output fet, so that only a 10 ohm resistor is used for a current > limiter > for the ICSPDAT and ICSPCLK lines. So that the current is too huge to be > able to drive the output therefore the voltage level will be dropped (as > described in the datasheet). Personally I do not like such exploitations, > it > is just interesting to see that at Microchip they design circuits like > this. > > Tamas > > > On Mon, Jul 14, 2008 at 8:13 AM, Wouter van Ooijen wrote: > >> Forrest W. Christian wrote: >> > I was curious too, since I use the '886 I figured I'd take a look... >> > It says in section 17.0, 25mA each I/O pin, or 90mA total. >> >> I know that figure is in that section, but where does it say that you >> can draw that amount of current and expect the chip to work? >> >> Section 17.0 is the absolute maximum ratings section. Nobody knows what >> that section is for (the standard that describes what "absolute maxima" >> is supposed to mean is not freely available), but it is certainly *not* >> for designing the operational state of a circuit. >> >> (Ok, I have some idea what that section it might be for: there are >> (short) circumstances, like a nearby lightning strike or a nuclear >> event, where you want to know what currents or voltages your chip can >> survive and be expected to work lateron.) >> >> -- >> >> Wouter van Ooijen >> >> -- ------------------------------------------- >> Van Ooijen Technische Informatica: www.voti.nl >> consultancy, development, PICmicro products >> docent Hogeschool van Utrecht: www.voti.nl/hvu >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > > > -- > Rudonix DoubleSaver > http://www.rudonix.com > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist