I can put it up on my website if you like: http://www.ubasics.com -Adam On Fri, Mar 26, 2010 at 7:56 PM, Dwayne Reid wrote: > At 04:40 PM 3/26/2010, James Newton wrote: > >>Dwayne, thanks for pointing out that 8, 14 and 20 pin chips can >>interchange... I assume some of the 18 pin chips can as well... very >>interesting... now if I can just connect the more commonly used components >>to the IO pins that will still be there if a smaller PIC is installed... >>ahh.. .more complexity in the design, I just love it. > > So far as I know, none of the 18 pin PICs are pin-compatible with the > 8/14/20 pin parts. > > I can send to you a copy of the layout that I use for the 14 pin > parts. =A0Its pretty useful - pins RA0, 1, 2, 4, 5 and all 6 port RC > pins are brought out to a simple but extremely flexible configuration > area. =A0This area allows each pin to be configured as input or output > with a variety of pull-up and pull-down networks. > > Pin RA3 is dedicated for power-up reset on these layouts - I rarely > need all of the pins anyway when I'm prototyping. =A0The block includes > a 78L05 or LP2950A TO-92 regulator with input & output bypass caps > and a J175 FET used for power-up reset (usable only if Vunreg is > above 11Vdc). =A0The pull-up on MCLR is a fairly low value so that Vdd > gets completely drained to 0vdc when power is removed. > > The input options for each available pin include: pull-up to Vdd or > Vunreg, pull-down to Gnd plus a separately configurable voltage > divider with optional zener clamp or filter capacitor. =A0Obviously, > there can be a series resistor on the pin if desired. > > The output options for each available pin include: series resistor, > TO-92 digital NPN (DTC143ES) open-collector output driver (B-C-E > pinout) with optional pull-up resistor to Vunreg, TO-92 digital PNP > open-collector output driver (E-B-C pinout) with optional pull-down > to GND. =A0You can substitute MOSFETs in place of the transistors > mentioned above but you may have to bend the pins around. > > Note that the "digital transistors" I mention above are transistors > with an integrated series resistor on the base plus shunt resistor > between B-E and are intended for use in logic circuits. =A0Rohm, NEC, > others make them. > > All of that in an area of 1.5" x 1.2". =A0Its intended to use all > through-hole parts but I've been known to glom SMD resistors and > capacitors down in various places when it was convenient to do so. > > Its easier to show it than it is to describe. > > > I've just block-copied that part of the layout from one of my board > layouts but the smallest I've been able to make it is about > 75K. =A0I'll send a copy to James and anyone else who asks for it > rather than dump another unwanted 75K file into everybody's mailbox. > > dwayne > > -- > Dwayne Reid =A0 > Trinity Electronics Systems Ltd =A0 =A0Edmonton, AB, CANADA > (780) 489-3199 voice =A0 =A0 =A0 =A0 =A0(780) 487-6397 fax > www.trinity-electronics.com > Custom Electronics Design and Manufacturing > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://chiphacker.com/ - EE Q&A site -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist