Robert Young wrote: > 1) RB6 / RB7 are the programming and debug pins. Yes, you can use them as I/O but you will loose your ability to use them as debug pins. Furthermore, you call out RB6 on your oddly shaped PIC twice. Are you sure I have RB6 on it twice? I had a look around the chip and can't find the second instance of it... please let me know! > 2) Component values not labeled in many cases. What FET/MOSFET are you using? Where is the value for the high and low side drivers? Etc. > I don't need any of those details on the schematic. I'll get my board made and then I'll have a think about it. > 3) No component numbering, again this can be a cause for confusion. U1, U2, D1, D2, R1, etc are quite helpful. -- Wait I retract part of that statement. I found some components are labeled but so small they are hard to see. And in some cases there are nets running through the text. And finally some have a "number" but most just have "?". > I'll get around to that. Protel has this "auto numbering" thing that will assign numbers for me. Where appropriate, I'll change the names to something more intuitive. > 5) Power? > At the moment I'm think of going from a 9 V square battery into an LM7805. I'll get around to that in due course. > 6) Ground? > Em... eh... the negative of the supply... ? > 7) Supply bypass caps? > What are they? > 8) Reset component values? Not familiar with the 16F887 but in general, for the "newer" PICs (16F and 18F) I was of the impression that a single pull-up resistor on MCLR/VPP is OK for the reset if you also have the POR bit set. For a production unit I'd think a bit more about the reset vs power supply turn on but for hobby and play seems OK. > I don't know about this stuff. I'll ask questions in due course. > 9) Pins for the 7-seg? Are you going to use something like a 74HC595 and SPI bus to control them? > Do you see the net names I put on the pins for the seven segs? Those nets go to the output of the high-side driver. (I originally did it by just drawing wire but it was way too messy). > 10) I've never been a big fan of the weak-pull ups in PORTB and unless I'm really pressed for power consumption I like a nice stiff pull up resistor. Again, _personal_ preference but I generally use a 47K for pull ups on a 5V design unless I need to minimize power and then I go through the exercise of computing currents versus expected duty cycle of the signal vs. input current HI/LO logic for the given PIC and its operating environment. For the one you have indicated on E1, what value? > Haven't thought about it yet. I'll wait til I get my board. Probably something like 10k though. > 11) What is hanging off of E2? > It's a piezo speaker :-D > 12) Internal oscillator? If nothing else, a quite note in the corner of the schematic about that. > I still have RB6 and RB7 free so I'm thinking of hooking up some sort of 20 MHz yoke-a-ma-jiggy to it. > 13) Un-used inputs on your driver chips should probably be tied to ground. Maybe through a resistor so you can use them later if you decide you want them. > Nice, thanks for that. It would have slipped my mind. > 14) If you switch to a common cathode 7-seg you could use your two spare high side drivers instead of the discrete FET/MOSFETs shown. > VERY NICE! Never crossed my mind! I'll look into it :-D -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist