Well, On your two micros, I suggest that you forget ERC and check your NETLIST or better yet open the design in PCBNEW and verify that you do indeed have two power rails.
--- In kicad-users@yahoogroups.com, Robert <birmingham_spi...@...> wrote: > > Thanks for your replies Carl and Andy. > > Speaking for myself, I have designs that use two instances of the same > micro, with each instance on a different supply rail. These micros all > have a power pin named VCC and I have no problems with ERC, so Kicad > isn't covertly connecting my VCC pins together. > > The OP (Mark) wants to have logic chips on two different supply rails, > but it seems that Kicad joins up all the hidden pins marked Vcc, even if > you connect the power pin to a different rail. Is the critical factor > that the pins are hidden, is it that the name case sensitive, or is it a > feature of multi-part components? It's not that the pin doesn't have a > number, because the logic chip symbols have both name and number > specified for the power pins (like the symbols I have created for > myself). What is the critical thing that Mark has to change to allow > him to connect two logic chips to two different supply rails. > > Regards, > > Robert. > > > > On 16/03/2010 11:14, Andy Eskelson wrote: > > Vcc IS the power to the chip, U2A in this case. > > so why have you connected +5V to it as well? > > > > DRC is detecting that you have effectively shorted VCC to a different 5V > > supply as well, and is complaining about it. > > > > Power flags are defined as power out pins, and you only have one power > > out on a power net,m if you add a second power flag DRC will complain > > about that as well. > > > > I think you are assuming that you need to connect 5 volts to the chip, > > and so are adding the +5V port, which is another independent supply net. > > Hence the confusion. > > > > The system works as has been mentioned by the power port names. When a > > device has a power pin with a specific name, AND you set the pin to be > > invisible you DO NOT need to connect anything else to it. As soon as you > > put a power port with the same name onto the circuit diagram, that port is > > automatically connected to all device power pins with the same name. > > > > > > A power net needs to be energised or DRC will complain. That can be done > > in two ways. Either a device such as a regulator can have a power out > > pin, which will indicate that it is energised, OR you add a power flag, > > which simply says that the net is energised. You use power flags in > > situations where you are connecting an external power source to your > > circuit via a connector, flying leads and so on. > > > > The one oddity is that GND is considered a power out type net as well, so > > it also needs energising with a power flag. > > > > logic IC's have generally had their power pins identified by names > > rather than the voltage, so you have Vcc Vss Vdd and so on. > > > > When you run into such chips, the same will apply, power ports of the > > same name are already considered to be connected to the physical supply > > > > Andy > > > > > > > > > > > > On Mon, 15 Mar 2010 16:13:15 -0000 > > "mtheling"<p...@...> wrote: > > > >> Hi Robert, > >> > >> if I connect for example a net "+5V" to a component U2A which has an VCC > >> input as invisible pin, I see that in PCBnew the pin is connected to the > >> "+5V" net as soon as I set an Powerflag to +5V. > >> But the ERC check in eeschema states this as error : > >> ErrType(5): Conflict problem between pins. Severity: error > >> @ (5,1000 ",6,7500 "): Cmp #FLG01, Pin 1 (power_out) connected to > >> @ (4,4000 ",6,7500 "): Cmp #FLG06, Pin 1 (power_out) (net 3) > >> > >> If I don't connect a Powerflag to the "+5V" net, in PCBnew the Power Pin > >> of U2A is still connect to the VCC net and not to "+5V" as set in the > >> schematic. > >> Please see schematic for example: > >> http://www.swapout.de/example_schematic.pdf > >> > >> What I am doing wrong? > >> > >> Thank you, > >> > >> best Regards, > >> Mark > >> > >> > >> > >> > >> ------------------------------------ > >> > >> Please read the Kicad FAQ in the group files section before posting your > >> question. > >> Please post your bug reports here. They will be picked up by the creator > >> of Kicad. > >> Please visit http://www.kicadlib.org for details of how to contribute your > >> symbols/modules to the kicad library. > >> For building Kicad from source and other development questions visit the > >> kicad-devel group at http://groups.yahoo.com/group/kicad-develYahoo! > >> Groups Links > >> > >> > >> > > > > > > ------------------------------------ > > > > Please read the Kicad FAQ in the group files section before posting your > > question. > > Please post your bug reports here. They will be picked up by the creator of > > Kicad. > > Please visit http://www.kicadlib.org for details of how to contribute your > > symbols/modules to the kicad library. > > For building Kicad from source and other development questions visit the > > kicad-devel group at http://groups.yahoo.com/group/kicad-develYahoo! Groups > > Links > > > > > > > > > > > > > > No virus found in this incoming message. > > Checked by AVG - www.avg.com > > Version: 9.0.790 / Virus Database: 271.1.1/2749 - Release Date: 03/15/10 > > 19:33:00 > > > > > No virus found in this outgoing message. > Checked by AVG - www.avg.com > Version: 9.0.790 / Virus Database: 271.1.1/2750 - Release Date: 03/16/10 > 07:33:00 >
